Preparation of a treatment of the family Apocynaceae for the Flore de Madagascar et des Comores necessitates the description of 11 new species and one new variety in subfamilies Periplocoideae (Baroniella effusa, Pentopetia suarezensis) and Secamonoideae (Calyptranthera punctulata, C. rosea, Pervillaea lanata, Secamone chouxii, S. dictyoneura, S. furcata, S. glabra, S. laevis, S. parviflora and S. toxocarpoides var. incana). Furthermore, an amended description of Pervillaea tomentosa is provided necessitated by an earlier confusion of this taxon with P. brevirostris (here synonymized) and with the new species P. lanata.
Citation: Klackenberg J. 2019: New species of Apocynaceae from Madagascar. – Willdenowia 49: 209–229. doi: https://doi.org/10.3372/wi.49.49210
Version of record first published online on 15 August 2019 ahead of inclusion in August 2019 issue.
During continuous studies of Apocynaceae for the Flore de Madagascar et des Comores, I have come across several specimens that do not fit into any known taxon and are here described as twelve new taxa in Baroniella Costantin & Gallaud (one species) and Pentopetia Decne. (one species) in subfamily Periplocoideae and in Calyptranthera Klack. (two species), Pervillaea Decne. (one species) and Secamone R. Br. (six species and one variety) in subfamily Secamonoideae. These genera are all endemic to the Madagascar-Mascarene area, except Secamone, which has a wide palaeotropical distribution.
Baroniella is a small, periplocoid genus of suffrutes-cent twiners endemic to the East Malagasy Phytogeographic Region (for the division into Phytogeographic Regions and Domains, see Humbert 1955), found from the littoral forest up to 1700 m altitude. In a revision of the genus (Klackenberg 1997b), seven species were recognized. More recently, two species have been added, B. collaris Klack. and B. linearifolia Klack., both from the littoral forest. Along with B. camptocarpoides Costantin & Gallaud, a rather common and widespread species in the littoral forest, B. effusa described below adds a fourth taxon from this habitat.
Pentopetia androsaemifolia Decne., found in Madagascar as well as in the Comoro and Assumption Islands, is the only species of Pentopetia known also from outside Madagascar. Representatives of the genus are known from all Phytogeographic Domains of Madagascar. Since the latest revision of the genus (Klackenberg 1999), P. viridis Klack. & Meve from Ampasindava and P. astephana Klack. from the Antsiranana area have been described. Together with P. suarezensis described below, 23 species are currently included in the genus.
Pervillaea was revised by Klackenberg (1996a). Four species were accepted, all endemic to Madagascar and distributed in the drier northwestern, western and southern parts of the island (West Malagasy Phytogeographic Region). Some years later, a fifth taxon, P. brevirostris Klack., was described as an endemic from Mauritius (Klackenberg 2007), but in the present article it is synonymized with P. tomentosa Decne. from northernmost Madagascar. With P. lanata described in the current article, the genus now comprises five species.
Calyptranthera was recognized by Klackenberg (1996b) based on a specimen previously placed in Toxocarpus Wight & Arn. In a revision one year later, four new species were added, all from the eastern, wetter part of Madagascar (Klackenberg 1997a). More recently, new species of Calyptranthera have also been found in northern and northwestern parts of the island in predominantly drier areas. However, these species are also confined to pockets with humid climate, viz. C. viridiflava Amman, L. Gaut. & Klack. from Sambirano Domain and C. gau-tieri Klack. from wetter parts of the Manongarivo massif in Central Domain as well as from Montagne d’Ambre, an isolated mountain forest surrounded by the drier Western Domain. Two species, C. sulphurea Klack. and C. vil-losa Klack., were described from the same humid forest in the Daraina area in Vohémar District, a phytogeo-graphically complex border area between Eastern, Western and Central Phytogeographic Domains. This distribution conforms with the pattern discussed by Nusbaumer & al. (2010), i.e. a phytogeographic connection between the evergreen lowland rainforest of Eastern Domain and those of Sambirano and of the isolated Ambre mountain, with Daraina as a link in between. With C. punctulata and C. rosea described below, 13 species are now recognized in this genus.
Secamone is a palaeotropical genus distributed in Africa from the Western and Eastern Cape Provinces of South Africa in the south to Senegal, the Republic of Central Africa and Socotra in the north. The genus is widely distributed in Madagascar and is also present on several smaller islands in the Indian Ocean. In Asia it is found from southern India and Sri Lanka and further eastward from Yunnan through SE Asia to New Caledonia and Australia. The genus was revised by Goyder (1992) and Klackenberg (2001) for continental Africa and by Klackenberg (1992a, 1992b) for Madagascar and Asia. Together with the six new taxa described below, 72 species are now known from Madagascar. The genus is represented in all Phytogeographic Domains of the island. All species found in Madagascar and the Comoro Islands are endemic to this area, except S. pachystigma Jum. & H. Perrier, which is also present in the Seychelles archipelago.
Material and methods
This study is mostly based on specimens from the herbaria BR, MO and P, collected during the last 20 years, in order to update an ongoing study for the Flore de Madagascar et des Comores. However, also material from G, GH, K, L, NY, S and US has been studied and cited (herbarium codes according to Thiers 2019+). The measurements and terminology of floral parts are in accordance with Klackenberg (1997a: fig. 2) for Calyptranthera and Pervillaea, with Klackenberg (1999) for Pentopetia, with Klackenberg (1997b) for Baroniella, and with Klackenberg (1992a: fig. 2, 3, 4; 2001: 318) for Secamone.
Baroniella effusa Klack., sp. nov. – Fig. 1.
Holotype: Madagascar, Fianarantsoa, Atsimo-Atsinanana reg., Farafangana, Mahabo Mananivo, Forêt d’Analazaha à l’est du fokontany Nosiala, 23°11′S, 47°41′E, 21 m alt., 29 Oct 2004, Ludovic, Jeannot & Emilson 933 (MO!; isotypes: P, TAN).
Diagnosis — Species haec Baroniellae camptocarpoidi in habitu similis sed differt lobis corollae brevioribus (< 5 mm) et stigmate cum lobis distinctis inter antheras protrudentibus.
Description — Suffrutescent, glabrous twiner. Leaves opposite; blade 2.5–5 × 1.5–3.5 cm, elliptic to obovate, cuneate at base, acute to apiculate at apex; venation pinnate; midrib and primary veins finely raised on upper surface, ± flush with lower surface when dry; petiole 3–4 mm long. Inflorescences longer than adjacent leaves, pendent, 4–20 cm long; cyme composed of several ± regular dichasia, with lower internodes 2–10 cm long, many-flowered; pedicels 3–10 mm long; bracts to 1 mm long. Calyx lobes 1–1.1 × 0.8–1 mm, about as long as corolla tube, very broadly ovate, broadly acute to rounded at apex; margin entire. Corolla narrowly ovoid in bud, fused for c. ¼ of its length into a tube, dull purple outside and white with pink centre inside; tube c. 1 mm long; lobes 3.3–3.5 × 1.7–2.1 mm, ovate, obliquely acute at apex. Corona forming an undulating ring at base; interstaminal lobes c. 0.3 mm high, rounded to truncate, reaching c. ½ way or more to style head. Anthers ± rectangular; filaments 0.4–0.5 mm long; elongation of connectives c. ½ as long as thecae. Translators with elliptic, 0.2–0.3 mm long spathe; stipe missing. Style including style head 0.8–0.9 mm high; style head discoid, with distinctly protruding apical portion, with 5 indistinct lobes opposite anthers and 5 longer interstaminal lobes protruding between stamens. Follicles c. 15 × 0.2 cm, curved and linear, slightly moniliform, recurved 45°–90° at base. Seeds not seen.
Phenology — Flowering specimens seen from October and November, in fruit from November.
Distribution and ecology — Baroniella effusa is known from two collections from Farafangana at c. 20 m altitude, one from littoral forest on sand and one from degraded forest.
Remarks — Baroniella effusa is in habit similar to B. camptocarpoides by its somewhat thick leaves with inconspicuous venation. Both species are found in the littoral forest. However, B. effusa is easily separated by the smaller flowers (< 5 mm long) gathered in profuse inflorescences and by the long style with discoid style head furnished with long lobes protruding between the anther filaments. The flowers in B. camptocarpoides are more than 5 mm long and the style head is obconical without protruding lobes.
Additional specimen studied — Madagascar: Fiana-Rantsoa: Atsimo-Atsinanana, S of Farafangana, near village of Mahabo, 20 m alt., 2001, McPherson & Rabenantoandro 18363 (MO).
Pentopetia suarezensis Klack., sp. nov. – Fig. 2.
Holotype: Madagascar, Prov. Antsiranana, Montagne de Français, 12°22′05″S, 49°21′E, 23 Jan 2002, De Block, Rakotonasolo & Randriamboavonjy 1365 (BR!; isotypes: G, K, MO!, P!, TAN).
Diagnosis — Species haec Pentopetiae boivinii foliis variegatibus similis sed differt bracteis valde longioribus, lobis coronae brevioribus et foliis pubescentibus.
Description — Suffrutescent, scrambling liana with younger branches hairy. Leaves opposite; blade elliptic, 20–35 × 10–20 mm, abruptly tapering to truncate at base, acuminate or apiculate at apex, hairy, when dry pale on lower surface and darker on upper surface but with contrasting paler midrib and primary nerves as well as leaf margin; venation looped, with veinlets reticulate when dry; midrib ± impressed on upper surface when dry, raised on lower surface; primary nerves ± flush with both surfaces when dry, diverging at c. 45° from midrib; petiole 5–10 mm long, hairy. Inflorescences axillary or terminal on short lateral branches, about as long as to shorter than adjacent leaves, to 3 cm long; cyme irregularly branched with both longer internodes to a few mm long and very short ones, umbel-like, 5–7-flowered; pedicels 10–15 mm long, hairy; bracts several, narrow, 4–6 mm long. Calyx lobes narrowly ovate, c. 4 × 1.3 mm, gradually narrowing and acute to acuminate at apex, much longer than corolla tube, often recurved, hairy at least along central part, ciliate along margin. Corolla with lobes fused for ⅕–⅙ of their length into a tube, white; tube 0.7–1.2 mm long, ± densely hairy inside and particularly below anther filaments; lobes oblong, 5–7 × 3–4 mm, bluntly acute and laterally notched at apex, lengthwise incurved, with a ± triangular boss at base, rotate to recurved, glabrous except for a patch of long hairs at each side of basal boss. Corona lobes 0.7–1 mm high, subulate to filiform, straight, as long as or shorter than filaments, glabrous. Staminal cone 2.4–2.7 mm high, distinctly exserted; filaments c. 1 mm long, filiform, slightly curved, inserted at mouth of corolla tube just below corona lobes, with long hairs near base inside; anthers c. 1.5 mm long, glabrous, with slightly protruding flat connective. Translators c. 1 mm long; spathe roundish, c. 0.5 mm long; stipe distinct, ± cylindric. Ovary and proximal part of style without longitudinal ridges. Style c. 1.5 mm long, glabrous; style head ovate in outline. Follicles not seen.
Phenology — Flowering specimens seen from January.
Distribution and ecology — Pentopetia suarezensis has hitherto been collected twice, both near Antsiranana (Diego Suarez), in deciduous forest on littoral sand or on limestone (tsingy).
Remarks — Pentopetia suarezensis is similar to P. boivinii Prain, a fairly common species from the littoral forests of the Malagasy E coast, by flower morphology but also by its variegated leaves when dry, i.e. the leaves have a darker upper leaf surface with contrasting pale areas along the midrib, larger veins and margin. It differs, however, by having shorter corona lobes but linear and much longer bracts. Pentopetia suarezensis and P. boivinii have similar, somewhat triangular bosses at the corolla lobes just outside the tube. In P. suarezensis, a patch of hairs on each side of these bosses is present, i.e. the petals are hairy also outside the tube. Pentopetia boivinii is hairy only inside the tube. In addition P. suarezensis differs by its smaller and hairy leaves with primary nerves that diverge at a narrower (c. 45°) angle from the midrib. In P. boivinii also young leaves are glabrous.
Another similar species to Pentopetia suarezensis is P. astephana. Both species have hairy and variegated leaves, and also a distinctly hairy corolla mouth. Pentopetia suarezensis differs by its short and widely funnel-shaped corolla tube topped by arched filaments of the anther cone and by its calyx lobes being almost twice as long as in P. astephana. It is furthermore characterized by its laterally notched corolla lobes. Although short, corona lobes are present in P. suarezensis (vs totally lacking in P. astephana).
Additional specimens studied — Madagascar: Antsi-Ranana: forêt d’Orangea, side closest to Ramena, De Block, Rakotonasolo & Randriamboavonjy 1375 (BR, MO).
Holotype: Madagascar, Toamasina, Alaotra Mangoro, Antampon’i Bevendra, 18°49′29″S, 48°57′09″E, 241 m alt., 26 Feb 2006, Andriambololonera 147 (P!; isotypes: MO!, P!, TAN).
Diagnosis — Species haec Calyptrantherae caudiclavae lobis coronae spathulatis et connectivi lobis filiforme prolongatis et corollis punctatis similis autem differt corollis majoribus et parte connectivii basali omnino pubescenti.
Description — Suffrutescent twiner with younger branches densely covered by erect, reddish hairs, glabrescent. Leaves opposite; blade 8–13 × 3–5 cm, elliptic to usually obovate, cuneate at base, acuminate to apiculate at apex, glabrous but with reddish hairs along midrib on lower surface and along margin; secondary nerves slightly raised on both surfaces when dry; veinlets reticulate; petiole distinct, 1–1.5 cm long, with reddish hairs. Inflorescences much shorter than adjacent leaves; cyme with few flowers, sparsely hairy to almost glabrous; pedicels 1–2 cm long; bracts and bracteoles triangular, c. 1.2 mm long. Calyx lobes c. 2.2 × 1.2 mm, much longer than corolla tube, triangular to slightly ovate, acute at apex. Corolla greenish with violet-brownish dots; tube c. 0.5 mm long; lobes 18–20 × 6–7 mm, elliptic, bluntly acute at apex, rotate, with 5 parallel veins, glabrous outside, finely hairy near base inside but also with two c. 2 mm long, submarginal rows of longer, distinct, somewhat bulbous hairs at each side. Staminal column in total c. 12 mm high (c. 1.5 mm with elongated portion of connectives excluded); filament cylinder below pollinaria entrances short; thecae and broader basal part of connectives distinctly hairy; connectives much elongated, at base dorsiventrally flattened and narrowly triangular, standing together in form of a cone, apically narrowing into 5 free, very thin, c. 1 cm long, filiform appendages. Corona lobes dorsiventrally flattened, c. 0.6 mm long, horizontal but folded, much shorter than connectives, glabrous, smooth, reddish brown. Pollinia not seen. Style narrow and cylindric but conical just below style head; style head c. 0.5 mm high. Follicles not seen.
Phenology — Flowering specimen seen from February.
Distribution and ecology — Calyptranthera punctulata is known only from the type locality in the New Protected Area (NAP) Sahifina near Brickaville (on label Antampon’i Bevendra) in the southern part of Antsinanana (on label Alaotra Mangory by mistake [Sylvie Andriambololonera, pers. comm.]) in disturbed forest at 241 m altitude.
Remarks — Calyptranthera punctulata is similar to C. caudiclava (Choux) Klack. and C. filifera Klack. These three species are all characterized by short and rotate corona lobes, and by their elongated connectives that basally are dorsiventrally flattened forming a usually cone-shaped calyptra above the thecae but apically transform to long and filiform appendages. Calyptranthera punctulata differs, however, by having the thecae and connectives densely covered by somewhat scale-like hairs. The apical parts of the connectives are evenly filiform, not club-shaped. It also differs by its corona lobes being dorsiventrally flattened and bent, almost folded, in contrast to the club-shaped lobes of C. filifera. Calyptranthera punctulata has flowers twice as large as C. caudiclava. In addition, it differs from C. caudiclava and particularly from C. filifera by its short (< 0.5 mm) basal tubular portion of the staminal column (the part below the entrances for the pollinia at pollination). In C. caudiclava and C. filifera this basal tubular portion of the filaments is distinctly longer, 1 mm long or more.
Calyptranthera rosea Klack., sp. nov. – Fig. 4B.
Holotype: Madagascar, Tôlanaro, Forêt de Mandena, 17 Mar 1985, Dorr 4018 (MO!; isotypes: P!, TAN).
– Calyptranthera caudiclava sensu Klackenberg in Adansonia, ser 3, 19: 29. 1997, pro parte quoad fig. 5A, B, E–G, non Toxocarpus caudiclavus Choux.
Diagnosis — Species haec Calyptrantherae caudiclavae lobis coronae spathulatis et connectivi lobis filiforme prolongatis similis autem differt corollis roseis.
Description — Suffrutescent twiner to c. 3 m high. Leaves opposite; blade 5–10 × 3–6 cm, oblong or obovate to very broadly elliptic, cuneate to truncate but sometimes minutely cordate at very base, acuminate to apiculate or rounded at apex, hairy on lower surface, more sparsely so on upper surface and glabrescent; veinlets reticulate and raised on lower surface but indistinct on upper surface when dry; petiole 1–1.5 cm long, when young densely hairy, glabrescent. Inflorescences shorter than adjacent leaves; cyme with short internodes on a 1–1.5 cm long peduncle; pedicels 1–1.5 cm long; bracts 2–3 mm long. Calyx lobes 2.3–3.5 × 0.8–1.5 mm, longer than corolla tube, ovate-triangular, acute at apex. Corolla purple-lavender to rose; tube 0.4–0.8 mm long; lobes 12–20 × 6–10 mm, elliptic, rounded at apex, glabrous outside or with a few scattered longer reddish hairs, glabrous inside except for a patch of straight, erect, white hairs near base including long, distinct, somewhat bulbous hairs in a submarginal row c. 1.3–2 mm long at each side; margin glabrous. Staminal column in total 8–10 mm high (1.7–2 mm with elongated portion of connectives excluded); filament cylinder below pollinaria entrances distinct; anthers glabrous; connectives much elongated, fused and broadened proximally forming a cone above thecae and crowned with 5 free, filiform to ± club-like appendages, glabrous. Corona lobes somewhat spathulate or club-shaped, 0.5–0.8 mm long, truncate at apex, rotate, much shorter than connectives, glabrous. Pollinia 0.1–0.15 mm long. Style narrow and cylindric proximally but slightly conical below style head, 1.2–1.5 mm high; style head 0.35–0.5 mm high. Follicles not seen.
Phenology — Flowering specimens seen from November, January and March.
Distribution and ecology — Calyptranthera rosea is distributed in the southeasternmost part of Madagascar. It grows in littoral forest on sand.
Remarks — In Klackenberg (1996a), this taxon was confused with Calyptranthera caudiclava (Choux) Klack. However, with more material of this genus accumulated from southern Madagascar accompanied with a re-evaluation of the type of C. caudiclava, it has become clear that the population from the littoral forest, here described as C. rosea, differs from C. caudiclava found in forests of some hundred metres altitude. In addition to C. caudiclava and C. rosea, a third species, C. filifera, is also known from the southern part of Madagascar. Calyptranthera rosea conspicuously differs by its bright rose-violet flowers in contrast to the dull greenish to brownish petals with reddish spots seen in the other two species, a col-our pattern also characteristic for the new C. punctulata described in this article (Fig. 4A). Furthermore, the elongated connectives (see Remarks to C. punctulata) stand tightly together forming a long and almost cylindric calyptra in C. rosea and the filiform appendages are more or less upright. In contrast, C. caudiclava, C. filifera and C. punctulata are furnished with more triangular connectives forming a conical calyptra that is topped by diverging appendages.
Additional specimens studied — Madagascar: Tôla-naro: Manafiafy (Ste Luce), 1990, Dumetz 1188 (MO, P); N of Tôlanaro, Manafiafy (Ste Luce), c. 4.5 air km W and slightly S of Manafiafy, 5 m alt., 1998, Lowry & al. 5005 (MO, P, S); Anosy Region. Fort Dauphin, Mahata-laky, Belavenoko S6 – 3.45–4 km E of Belavenoko, 17 m alt., 2011, Ratovoson 1784 (MO).
Pervillaea lanata Klack., sp. nov. – Fig. 4C.
Holotype: Madagascar, Antsalova, 2 Apr 1993, Villiers, Klackenberg & Badré 5007 (S [specimen mounted on 2 sheets: S07-6993! & S07-6996!]; isotypes: K, MO!, P!).
– Toxocarpus tomentosus sensu auct. div. incl. Jumelle & Perrier de la Bâthie in Ann. Mus. Colon. Marseille, ser. 2, 5: 391. 1907 and in Ann. Mus. Colon. Marseille, ser. 2, 6: 214. 1908 (extended descr.), non Pervillaea tomentosa Decne.
– Pervillaea tomentosa sensu Klackenberg in Nordic J. Bot. 16: 174. 1996, pro parte quoad fig. 4, 5A, E, non Decne.
Diagnosis — Species haec habitu Pervillaeae tomentosae primo adspectu maxime similis sed differt inflorescentiae ramis magis crassis et longis, connectivis multo longioribus et corollis majoribus atque roseis albescentibus.
Description — Suffrutescent, woolly twiner to 8 m high. Leaves opposite; blade narrowly ovate to usually elliptic or broadly ovate, 8–17 × 6–12 cm, cuneate to truncate or cordate at base, acuminate to apiculate at apex, with entire margin, with dense curled whitish hairs on lower surface and sparser ± straight hairs on upper surface; venation pinnate and somewhat arched, reticulate; midrib and primary nerves distinctly raised on lower surface; petiole distinct, thick, 1.5–4 cm long, woolly. Inflorescences c. ½ as long as adjacent leaves or rarely longer; cyme lax, rather many-flowered, woolly; pedicels often in pairs, 2–4 mm long; bracts usually very short to 3 mm long. Calyx lobes narrowly triangular to ovate, 2.7–4.3 × 1.3–1.6 mm, longer than corolla tube, acute at apex, with long, wavy, dense hairs on both surfaces. Corolla contorted with left lobe margin overlying, not twisted, with lobes fused for ⅕– of their length into a tube, glabrous inside but rarely with a few scattered longer hairs outside, first pale reddish outside and darker red inside but becoming white; tube c. 2 mm long; lobes narrowly oblong to narrowly obovate, 9.5–11.5 × 2.3–3.9 mm, rounded at apex. Staminal column 1–1.2 mm high (connectives excluded); thecae glabrous; connectives projecting long above thecae forming a cone, 1.2–2 mm long, glabrous. Corona lobes narrowly triangular, 2–3 mm long, gradually tapering toward apex, straight, slightly longer to almost 2 × as long as connectives, glabrous; margin usually entire but sometimes with irregular teeth. Pollinia elliptic to ovate, 0.18–0.27 mm long. Style head with short, broader than high, 0.3–0.5 mm high apical portion. Follicles narrowly ovate to narrowly oblong in outline, 7–14 × 2–3 cm, not recurved or recurved c. 90°, gradually tapering toward acute apex but seeming rounded to truncate because of indumentum, covered with very dense, long, wavy, intertwining hairs. Seeds c. 10 mm long; hairs c. 2 cm long.
Phenology — Flowering specimens seen from January, March and April, in fruit from January, March, July and August.
Distribution and ecology — Pervillaea lanata is distributed in the northwestern half of Madagascar in Western Domain. It has been found in usually dry, sometimes degraded forest on sandy soil up to 120 m altitude.
Remarks — Decaisne (1844) described Pervillaea tomentosa from northeasternmost Madagascar. Some 60 years later, Perrier de la Bâthie collected extensively in the northwestern part of the island and came across what he believed to be the same species as Decaisne's P. tomentosa, although he considered this taxon better placed in Toxocarpus Wight & Arn. (Jumelle & Perrier de la Bâthie 1907). Klackenberg (2007) described P. brevirostris as an endemic from Mauritius. However, an analysis of recently collected material, together with a re-examination of the type of P. tomentosa (Vohémar, Richard 91), shows the Mauritian P. brevirostris and the Malagasy P. tomentosa to be conspecific, and P. brevirostris is here placed in synonymy of P. tomentosa. In contrast, the Malagasy northwestern population of what has been conceived as P. tomentosa (Toxocarpus tomentosus sensu Jum. & H. Perrier) differs in several characters from the northeastern population and is here described as P. lanata. A new description of the more narrowly circumscribed P. tomentosa including P. brevirostris and a list of material referred to this species are presented below.
Pervillaea lanata and P. tomentosa are easily distinguished by their large and broad leaves, much larger than the leaves of the other taxa of this genus. Flowering branches in P. lanata bear broadly ovate, usually cordate leaves. On vegetative branches, the lamina is usually narrower, narrowly ovate to elliptic and with a truncate to tapering base. The petals are reddish but turn white in late anthesis. This is in contrast to the greenish yellow ones covered with purple dots that are characteristic for P. tomentosa. Furthermore, the corolla lobes are longer (c. 1 cm long in P. lanata vs usually 5–6 mm long in P. tomentosa) and the inflorescences are larger in all parts (5–10 cm long in P. lanata vs less than 5 cm long in P. tomentosa). The connectives are distinctly elongated above the thecae in P. lanata, about as long as the corona lobes and directed upward forming a cone above the style head. In P. tomentosa these elongated connectives are small, broadly triangular and directed horizontally forming a lid directly above the style head.
For additional illustrations of Pervillaea lanata, see Klackenberg (1996a: fig. 4A–G, 5A, E).
Additional specimens studied — MADAGASCAR: MA-HAJANGA: the dunes, 30 Mar 1912, Afzelius s.n. (MO, NY, P, S); Besalampy, Jun 1906, Alleizette s.n. (L); Madagascar s. loc., Baron 4789 (P); baie de Bombetoka, au bord de la mer, 1839, Bojer s.n. (mixed collection, also one piece of Pervillaea tomentosa) (P); Boeny, à 15 km au nord-ouest de la ville Mahajanga, au sud-ouest de la rivière Morira, entre les villages Mangatsa et Antsianitia, 5 m alt., 2007, Callmander & Phillipson 676 (MO, P); entre Boriziny (Port Bergé) et la Sofia, 1973, Cremers 2429 (MO, P); sud de Besalampy, Decary 8064 (K, P); Maintirano, 1930, Decary 8242 (P); plateau d’Ankara, 1900, Perrier de la Bathie 1098 (P); Manongarivo, 1903, Perrier de la Bathie 1098 (same no.!) (P); plateau d’Antanimena entre la Ma-havavy et la Betsiboka, 1905, Perrier de la Bathie 1098 (same no.!) (P); Boiny et Ambongo, Perrier de la Bathie 1098 (same no.!) (P); env. de Marovoay, Ankarafantsika, 1910, Perrier de la Bathie 9011 (MO, P); entre la Manam-bolo et la Tsiribihina, 1911, Perrier de la Bathie 11771 (P); env. de Marovoay, 1908, Perrier de la Bathie 11780 (P); route vers la forêt de Mangabe, 90 m alt., 1995, Rakotoma-laza & al. 388 (BR, MO); Ambato Boeni, Tsaramandroso, Bevazaha, Réserves Naturelles: RN 1880 Ramamonjisoa (P); Ankarafantsika, Bevasaka, 120 m, s. coll. 66 (P, US).
Pervillaea tomentosa Decne. in Candolle, Prodr. 8: 613. 1844; K. Schum. in Engler & Prantl, Nat. Pflanzenfam. 4(2): 291, fig. 85W–Y. 1895. – Lectotype (designated by Klackenberg 1996a: 174): trouvé à Vohémar, à la Baie de Ringy ou Lingwaton, Richard 91 (P!).
= Pervillaea brevirostris Klack. in Bot. Jahrb. Syst. 126: 204, fig. 1. 2005, syn. nov. – Holotype: Mauritius, Duncan 12 (K!).
Description — Suffrutescent, densely hairy twiner to 8 m high. Leaves opposite; blade ovate to usually elliptic to broadly elliptic, 5–11 × 3.5–7 cm, cuneate to truncate at base, obtuse but usually finely apiculate at apex, on lower surface with dense, curled, reddish hairs when dry, on upper surface with sparser, ± straight, whitish hairs; margin flat, entire; venation pinnate and arched near margin, indistinctly reticulate when dry; midrib and primary veins raised on lower surface, impressed or ± flush with upper surface; petiole distinct, 1–3 cm long, densely hairy with curled, reddish hairs. Inflorescences usually slightly longer than adjacent petiole but distinctly shorter than leaf, covered by dense, reddish hairs; cyme rather lax with 5–10 flowers, irregularly branched; pedicels 3–5 mm long; bracts 2–6 mm long, narrow. Calyx lobes narrowly triangular to lanceo-late, 2.7–3.4 × 1.2–1.7 mm, much longer than corolla tube, acute at apex, with long, wavy, dense hairs on both surfaces. Corolla contorted with left lobe margin overlying, not or only slightly twisted, with lobes fused for ⅕–⅙ of their length into a tube, glabrous on both surfaces, greenish yellow with purple spots; tube 1.2–1.7 mm long; lobes oblong to elliptic or obovate, 5.4–6.4(–8.7) × 2.7–4 mm, usually rounded at apex. Staminal column 0.6–0.8 mm high (corona lobes excluded); connectives elongated, bent above thecae at 90° inward covering style head, glabrous. Corona lobes narrowly triangular to linear, directed outward but bent upward apically, 0.7–1 mm long, distinctly longer than elongated connectives, glabrous; margin entire. Pollinia elliptic to ovate, c. 0.15 mm long. Style head with broad and short apical portion, slightly depressed at centre, c. 0.1 mm high. Follicles narrowly ovate to narrowly oblong in outline, 7–14 × 2–3 cm, recurved c. 90°–135°, gradually tapering toward acute apex but seeming rounded to truncate because of indumentum, covered with very dense, long, wavy, intertwining hairs. Seeds 13–15 mm long; hairs 3–4 cm long.
Phenology — Flowering specimens seen from January to March and October, in fruit from April to May and November to January.
Distribution and ecology — Pervillaea tomentosa is known from the northeasternmost tip of Madagascar, but also from a 150-year-old collection from Mauritius. It has been found in dry deciduous, dense to degraded forest on sand up to 290 m altitude.
Remarks — For an illustration of Pervillaea tomentosa, see Klackenberg (2007: fig. 1). Diagnostic characters are discussed under Remarks to P. lanata.
Additional specimens studied — Madagascar: sine loco: Blackburn s.n. (GH, K); 1961, Bosser 14854 (MO, P). — Antsiranana: Sava, bord de la route entre Antalaha et Sambava à 13 km au sud de Sambava, 12 m alt., 2010, Aubriot 177 (P); Ramena, Ambodivahibe, Ampio 2.5 km au nord-ouest du village d’Ambodivahibe, 2005, Jullet Be & al. 105 (MO, P); Andrafiabe, Ambolobozokely, An-jialava, 3 km au nord du village d’Amolobozokely, 2005, Jullet Be & al. 133 (MO, P); Antsiranana-Ambilobe, Ma-hamasina, Massif de l’Ankarana, Betsimipohaka, 150 m alt., 2003, Bardot-Vaucoulon 1350 (MO, P); Antsiranana (Diego Suarez), Mafaly, Bernier 130 (P); Vohémar, Boivin 2472 (P); Jard. Bot. Tsimbazaza d’origine de la region d’Antalaha, 1962, Bosser 19800 (P); Massif d’Antsahabe, Vohémar, Daraina, 2004, Callmander & al. 247 (MO, P); Sava, Vohémar, Nosibe, Anjiabe, Anaborano, forêt littorale d’Analabe, Antovonjianivo, 34 m alt., 2004, Manja-kahery & Sola 89 (MO); Ramena, Baie des Sakalava, à 3.5 km à l’est du fokontany Ankorokihely, 10 m alt., 2004, Leopold & al. 12 (MO, P); Forêt d’Orangea, along dirt track near remains of French fort on hill above Ramena, 50 m alt., 2003, Miller & al. 10722 (MO, S); Vohémar, Daraina, forêt de Bekaraoka, 180 m alt., 2004, Nusbaumer & Ranirison LN 1190 (G, P, S); Vohémar, Nosy be, Anjiabe, forêt d’Analabe, 2004, Rabehevitra & al. 927, 972 (MO); Vohémar, Tsarabaria, Manakana, forêt sublittorale d’Ambondrobe, 2003, Rabevohitra & al. 4578 (MO); Vohémar, Nosy be, Anjabe, forêt littorale d’Analabe (Anaborano) près du lac Sahaka, 5 m alt., 2003, Rabenantoandro & al. 1346 (MO); Diana Region, Andrafiabe, à 2 km ouest du village d’Ambolozobe, forêt d’Ankonahona, 20 m alt., 2007, Rakotonandrasana 1092 (MO); Diana, Andrafiabe, Ambolobozokely, Anosy, 3 m alt., Rakotonandrasana & al. 1147 (MO); Vohémar, Daraina, Ambatoharanana, Ankijabe, forêt de Bembosa, à 2 km à l’ouest d’Ankijabe, 200 m alt., 2005, Randrianaivo & al. 1283 (MO); Sava, Vohémar, Vohimarina, Fanambana, Antsatoby, 109 m alt., 2007, Rasoafaranaivo 210 (MO, P); Vohémar, Richard 69 (P); Diana region, forêt d’Ambararata, Orangea Peninsula, 50 m alt., 2005, Schatz & al. 4255 (MO). — Madagascar?, Mauritius?, Seychelles?: [presented by Admiral Bowles 17 July 1863] (MO).
Holotype: Madagascar, Toamasina, Moramanga, Andasibe. Menalamba, Analamay, 18°48′43″S, 48°20′20″E, 1060 m alt., 10 Nov 2005, Razanatsoa, Antilahimena & Edmond 144 (MO!; isotypes: P, TAN).
Diagnosis — Species haec Secamonae obovatae affinis sed differt foliis minoribus et capite stigmatis breviore columna staminali solum duplo longiore vel corollis viridi-rubiscentibus.
Description — Suffrutescent twiner to small, scrambling shrub to 4 m high; branches ± divaricate with youngest parts covered with reddish hairs. Leaves opposite, somewhat coriaceous and revolute at very margin; blade 1.5–2.5 × 0.5–1.5 cm, narrowly elliptic to usually obovate, tapering at base, acute to truncate but usually obtuse at apex and sometimes apiculate, glabrous; venation faintly or not visible except for distinct midrib; midrib impressed on upper surface, raised on lower surface for larger part; epidermis ± smooth on both surfaces; petiole 3–6 mm long, glabrous or with few hairs. Inflorescences extra-axillary (sometimes seeming terminal), shorter than adjacent leaves; cymes rather dense, irregularly reduced and with a few umbels on short axes, few- to 5-flowered, densely pubescent; axes few, usually very short but sometimes to 2 mm long, thick; pedicels 4–6 mm long; bracts minute to 1 mm long, often early deciduous. Calyx lobes 1–1.3 × 0.6–0.7 mm, oblong to ovate, rounded to obtuse at apex, with few reddish hairs mostly along margin and at apex. Corolla ± conical in bud and rounded to usually subacute at apex, fused for ¼–⅕ of its length into a tube, contorted with left lobe margins overlying, not twisted, with hairs directed inward or bent upward in filled triangles at mouth inside (esp. along lateral ridges), yellowish to usually greenish, reddish toward base of lobes inside, dark when dry; tube 1.3–1.7 mm long; lobes spreading, 4.1–6 × 1–1.4 mm, narrowly oblong with ± asymmetric, rounded to obtuse apex to narrowly triangular with subacute apex and often revolute margin, thin. Staminal column 0.8–1 mm high. Corona lobes 0.6–0.8 mm long (free part), basally with flat back but laterally compressed toward apex, falcate, ± equalling staminal column. Pollinia c. 0.1 mm long. Style head projecting c. 2 × longer than staminal column; apical portion c. 2 × as long as basal portion, 1–1.2 mm long, slightly fusiform, entire. Follicles c. 5.5 × 0.2 cm, linear, thin-walled, sparsely hairy (only 1 follicle seen). Seeds not seen.
Phenology — Flowering specimens seen from October, November and January, in fruit from November.
Distribution and ecology — Secamone chouxii is found in humid, sometimes degraded forest at altitudes of 1000–1200 m in eastern Madagascar.
Remarks — This species is similar to Secamone obovata Decne. from the littoral forest, but it differs by its smaller leaves, longer pedicels (4–5 mm long) and larger corolla (c. 7 mm long), albeit with a shorter style head protruding only about twice as long as the staminal column. Secamone chouxii differs also by having greenish flowers that are tinged with red in two indistinct lines toward the base (Fig. 6A) (vs entirely white-yellowish in S. obovata).
This species is named after Pierre Choux, a French specialist in Malagasy Asclepiadaceae, who significantly contributed to the study of Secamone.
Additional specimens studied — Madagascar: Toa-Masina: Moramanga, Andasibe, Menalamba, Ambatovy, Analamay forest, 1073 m alt., 2005, Antilahimena & Edmond 4171 (MO); ibid., Antilahimena & al. 5991 (MO photo!); Alaotra-Mangoro reg., along road to Lakato, c. 18 km S of Rt 2, just S of small village, 1050 m alt., 2004, Lowry & al. 6542 (S); fiv. Ambatondrazaka, commune Antanandava, Parc National de Zahamena, Cam-pement Bemoara, 2 km au sud-est d’Ankosy à côté de la rivière Manambato, 1200 m alt., 2002, Rakotonandrasana 633 (MO); 17 km S of Route Nationale 2 (Antananarivo to Toamasina), along road to Lakato, 1080 m alt., 2003, Schatz & al. 4177 (S); near Andasibe. Forest of Mantadia, beyond the graphite mine, 1000–1200 m alt., 1994, Van der Werff & al. 13785 (BR, S).
Holotype: Madagascar, Toamasina, Alaotra-Mangoro, Fivondronana Moramanga, Commun Andasibe, Fokontany Menalamba. Andranovery forest / Ambatovy forest, 18°51′32″S, 48°18′34″E, 1031 m alt., 24 Jan 2008, Antilahimena & Ralaisabotsy 5977 (MO!; isotypes: P, TAN).
Diagnosis — Species haec Secamonae marsupiatae flo-ribus paucis parvis urceolatis et caulibus indumento fer-rugineis similis sed differt nervatura in sicco manifeste prominenti in superficiebus ambabus folii et foliis ellip-ticis cuneatis.
Description — Suffrutescent twiner or scrambling shrub to 8 m high; younger branches covered with ± erect, reddish hairs. Leaves opposite, somewhat coriaceous, flat but revolute at very margin; blade 2–3.5 × 0.8–2 cm, elliptic, cuneate at base, acute at apex, glabrous but hairy along basal part of midrib on both surfaces and sometimes also along margin; venation pinnate, spreading, looped near margin, ± reticulate and very distinct on both surfaces when dry; midrib and primary nerves on both surfaces distinctly raised when dry; epidermis smooth on both surfaces, shining on upper surface; petiole 1–2 mm long, hairy. Inflorescences extra-axillary along branches, shorter than adjacent leaves; cymes dense with shortened axes, few-flowered, ± hairy; pedicels 1.3–1.9 mm long, glabrous; bracts c. 0.5 mm long, hairy. Calyx lobes c. 0.6 × 0.6 mm, broadly triangular, acute to rounded at very apex, sparsely hairy outside, glabrous inside, finely ciliate along margin. Corolla ovoid in bud and rounded at apex, fused for ⅔–¾ of its length into a tube, lobes valvate, not twisted, with a small patch of hairs below each lobe in proximal ½ of tube inside, yellow; tube c. 1.6 mm long, slightly pitcher-shaped; lobes slightly bent outward, c. 0.7 × 0.8 mm, broadly triangular, rather thick, subacute to rounded at apex. Staminal column c. 0.8 mm high. Corona lobes c. 0.6 mm long (free part), dorsiventrally compressed, erect, longer than staminal column; basal part ± as broad as lobe, attached along c. ½ of stamen, with 2 distinct, pouch-like structures at bases of sclerified margins (anther wings). Pollinia less than 0.1 mm long. Style head projecting above staminal column, about as long as corona lobes; apical portion c. 0.5 mm long, about as long as basal portion, broadened at apex, faintly bilobed. Follicles 3–5 × 0.3–0.5 cm, narrowly ovoid to almost linear, thin-walled, glabrous or with sparse, short hairs, recurved ± 45°. Seeds not seen.
Phenology — Flowering specimens seen from January, March to May and October, in fruit from January to June, September and October.
Distribution and ecology — Secamone dictyoneura is known from montane forests of eastern Madagascar, mostly collected in the Moramanga-Andasibe area at altitudes of 850–1250 m.
Remarks — Secamone dictyoneura is similar to S. marsupiata Klack. from the same habitat in northern Madagascar. Both species have small, slightly pitcher-shaped flowers in short, few-flowered cymes, and stems covered with ferruginous, erect hairs. Secamone dictyoneura differs by having slightly larger corona lobes that reach about as high as the style head, by its larger and more elliptic leaves with cuneate bases (vs ovate and more or less truncate bases in S. marsupiata) and particularly by the leaves having more prominent venation, distinctly reticulate by fibrous veinlets also on the lower surface (vs much less prominent veinlets on the lower than on the upper surface when dry in S. marsupiata).
Additional specimens studied — Madagascar: Toa-masina: Antsinanana reg., Distr. Brickaville, Commune Maroseranana, Fkt. Ambodilendemy, Ankerana, 873 m alt., 2011, Antilahimena & al. 7736 (MO). — Toa-masina: Alaotra Mangoro, Moramanga: Andasibe, Menalamba, Berano, Avondrona forest, 1015 m alt., Antilahimena & al. 6822 (MO); Andranovery, forêt d’Andranovery, 1031 m alt., 2009, Bernard 1434 (MO, S); commune rurale Morarano Gara, Fkt. Ambo-hibolakely, Forêt d’Anambofampana, corridor Forestier Analamay Mantadia, 960 m alt., 2012, Rakotovao 5882 (MO); Analamay, forêt de Mahatakatra, Analamay côté nord-nord-ouest, 1007 m alt., 2008, Randrianasolo 1051 (MO); Morarano, Marovoay, forêt de Mahatakatra, 997 m alt., 2008, Ravelonarivo 3150 (MO). — Moramanga: Ambohibary, Ampitambe: lambeau forestier d’Ankoditrazo, 973 m alt., 2009, Andriamiarinoro & al. 156 (MO); Ambatovy, forêt d’Analamay, 1092 m alt., 2008, Andriantiana & al. 475 (MO); ibid., 1102 m alt., 2008, Andriantiana & al. 492 (MO); Ambatovy, forêt d’Ampanadiofanantsy, route vers Befotsy, 1021 m alt., Andriantiana & al. 548 (MO); ibid., 996 m alt., 2008, Andriantiana & al. 572 (MO); Ambatovy. Ambatotsiandro-rana forest, 1035 m alt., 2008, Antilahimena 6572 (MO); Ambatovy / Andranovery forest, 1068 m alt., 2007, Antilahimena & Marcelin 5930 (MO); Vavanaomby forest, 1024 m alt., 2007, Antilahimena & al. 5261 (MO); ibid., 1032 m alt., 2008, Antilahimena & al. 6089 (MO); Am-boasarikely forest, 1062 m alt., 2008, Antilahimena & al. 6469 (MO); Ambatovy, Ampangadiatrandraka, 1014 m alt., 2009, Bernard & al. 1445 (MO); NE of Moramanga, at nickel-mining exploration site, Ambatovy, 1000 m alt., 1998, McPherson 17532 (S); Ambatovy, 965 m alt., 2005, Phillipson & al. 5761 (MO); Forêt d’Analamay, 1067 m alt., 2008, Rakotandrajaona 630 (MO); ibid., 1033 m alt., 2008, Rakotandrajaona 677 (MO); Andasibe, Menalamba, 11 km E d’Ampitambe, Ambatovy, 1004 m alt., 2005, Rakotovao & Edmond 1856 (MO); Ambatovy, environ 22 km NE de Moramanga, 1027 m alt., 2005, Rakotovao & al. 1541 (MO); Ambatovy, Andranovery, 1002 m alt., 2008, Randrianasolo 659 (MO); Forêt d’Ambatovy, 1029 m alt., 2008, Ratolojanahary 52 (MO); Ambatovy, forêt de Vodibasy, 1145 m alt., 2010, Ravelonarivo & Radona 3397 (MO); Ambatovy, forêt d’Antranolambo, 989 m alt., 2008, Ravelonarivo & al. 3172 (MO); Ambatovy, 1111 m alt., 2011, Rasoazanany & al. 23 (MO); Ambatovy, entre Tapimbato et Berano, 1215 m alt., 2005, Razanatsoa 106 (MO); Antsangimaso, Ambatovy, 1044 m alt., 2005, Razanatsoa 342 (MO).
Secamone furcata Klack., sp. nov. – Fig. 8.
Holotype: Madagascar, Antsiranana, Faritra Sava, Vohémar, Daraina, Ankarafa, Antsahabe, 5 km à l’ouest du village de Daraina, 13°12′41″S, 49°33′35″E, 644 m alt., 5 Nov 2005, Jullet Be & al. 216 (MO!; isotypes: CNARP, P!, TAN)
Diagnosis — Species haec Secamonae tsingycolae similis sed lobis coronae uncinatis et capite stigmatis distincte bilobato differt.
Description — Suffrutescent twiner; branches ± divaricate, with white to somewhat reddish hairs. Leaves opposite, herbaceous, flat at very margin; blade 5–6 × 2–2.5 cm, elliptic, cuneate to truncate at base, usually shortly caudate at apex, pubescent; indumentum of white, erect, straight to slightly curved hairs on both surfaces, denser along midrib, not intertwined; venation pinnate, looped, ± reticulate on both surfaces; midrib impressed to flush with upper surface, distinctly raised on lower surface; epidermis smooth; petiole c. 5 mm long, densely pubescent as midrib. Inflorescences extra-axillary, much shorter than adjacent leaves; cymes 1- to probably usually few-flowered, densely hairy; axes reduced; pedicels 1.8–2 mm long; bracts to 2 mm long, narrow. Calyx lobes 1.6–2 × 0.5–0.8 mm, longer than corolla tube, triangular to ovate, acute at apex, with dense, probably reddish hairs outside, glabrous inside. Corolla cylindric in bud and gradually narrowing from base, obtuse to subacute at apex, fused for c. ¼ of its length into a tube, contorted with right lobe margins overlying, very slightly twisted to right, with short hairs at base of lobes and distal part of tube, yellow, dark when dry; tube c. 0.8 mm long; lobes probably ± spreading, c. 3.5 × 1.2 mm, narrowly oblong, rounded to subacute at apex, thin. Staminal column c. 1 mm high. Corona lobes c. 0.7 mm long (free part), dorsiventrally compressed, curled to hooked at apex, projecting above staminal column; basal part with rounded back, narrower than lobe, attached along c. of stamen. Style head projecting c. ½ longer than staminal column, longer than revolute corona lobes; apical portion slightly longer than basal portion, c. 0.8 mm long, broadened and distinctly bilobed at apex. Follicles c. 5.5 × 2 cm, ovoid, very thick-walled, with dense, short hairs, recurved c. 90°. Seeds 7–8 mm long; hairs 1.5–2 cm long.
Phenology — Flowering specimen seen from July and November, in fruit from July.
Distribution and ecology — Secamone furcata is known up to 650 m altitude by two collections from the very north of Madagascar, one collected in dry forest on sand and the other in transitional forest on rocky ground.
Remarks — Secamone furcata is similar to S. tsingycola Klack., a taxon known only by the type specimen described from the tsingy of Bemaraha. Both species have floral parts of about the same size in very short inflorescences and the leaves are covered by erect hairs. Secamone furcata, however, is distinguished by the apical portion of the style head being obconical with two short but distinct lobes (vs basally cylindric but toward the apex spherically broadened and only finely cleft at the very apex in S. tsingycola). The corona lobes are hooked to curled and not overtopping the style head (vs broadened toward the apex, upright and overtopping the style head in S. tsingycola). On the other hand, the large and thick-walled fruits are similar to those seen in S. ankarensis (Jum. & H. Perrier) Klack. and S. uniflora Decne. The fruits of these three species, however, can be distinguished by their indumentum, which is the same as for the leaves, i.e. thick with bent and curled hairs in S. ankarensis, lacking or with very sparse, short and appressed hairs in S. uniflora and rather thick but with more or less straight hairs in S. furcata. Also, in S. ankarensis and S. uniflora, furcate style heads are present. In contrast to the short lobes in S. furcata, however, these style heads are furnished with conspicuously long lobes that protrude high above the staminal column. Fruiting material of S. tsingycola is not known.
Additional specimen studied — Madagascar: Antsiranana: Andrafiabe, Sahafary, 191 m alt., Guittou & al. 54 (MO).
Secamone glabra Klack., sp. nov. – Fig. 9.
Holotype: Madagascar, Antsiranana, Fivondronana Vohémar, Firaisana Nosy be, Fokontany Anjiabe. Analabe (Anaborano) près du lac Sahaka, 13°04′53″S, 49°54′03″E, 5 m alt., 25 Feb 2003, Rabenantoandro & al. 1337 (MO!).
Diagnosis — Species haec Secamonae obovatae et prae-sertim S. toxocarpoidi similis sed differt corolla glabra et corollae tubo angustiore.
Description — Suffrutescent twiner to small, scrambling shrub; branches ± divaricate with younger parts covered with reddish hairs, glabrescent. Leaves opposite, somewhat coriaceous, revolute at very margin; blade 2–4 × 1–2.5 cm, elliptic to broadly obovate, cuneate to tapering at base, broadly acute to retuse at apex and sometimes apiculate, glabrous but sometimes with short, reddish hairs along midrib when young; venation not visible except for distinct midrib or faintly pinnate; midrib impressed on upper surface, raised on lower surface; epidermis ± smooth on both surfaces; petiole 3–5 mm long, usually pubescent as blade. Inflorescences extra-axillary, shorter than adjacent leaves; cymes dense, much and irregularly condensed, few- to rather many-flowered, densely pubescent; axis usually very short to 2 mm long, thick; pedicels very short to 2 mm long; bracts minute. Calyx lobes 1.1–1.7 × 0.4–0.6 mm, narrowly triangular to narrowly ovate, acute but rounded at very apex, with reddish hairs outside and also at very apex inside. Corolla cylindric in bud and gradually narrowing from base, subacute at apex, fused for c. ⅕ of its length into a tube, contorted with right lobe margins overlying, slightly twisted to left, glabrous except for some reddish hairs at very tip in bud, yellowish to greenish cream; tube 1.2–1.4 mm long; lobes probably ± erect, 5–5.4 × 1.2–1.5 mm, narrowly oblong, acute, but obtuse at very apex, thin. Staminal column 0.6–0.7 mm high. Corona lobes c. 0.5 mm long (free part), dorsiventrally compressed, straight, slightly projecting above staminal column; basal part flat, broader than lobe, attached along c. ½ of stamen. Pollinia c. 0.1 mm long. Style head projecting 3–3½ × longer than staminal column; apical portion 3–4 × longer than basal portion, 2–2.5 mm long, not broadened at apex, entire. Follicles not seen.
Phenology — Flowering specimens seen from February and November.
Distribution and ecology — Secamone glabra is known from the Vohémar region. It has been found in littoral forest on sand at altitudes up to 20 m.
Remarks — This species is similar to Secamone toxocarpoides Choux. Secamone toxocarpoides together with S. bemaharensis Klack., S. sulfurea (Jum. & H. Perrier) Klack. and S. valvata Klack. form a group of species characterized by dense and short inflorescences, long and narrow corolla lobes and a long and protruding style head, as well as by a dark olive green upper surface of the leaves when dry. The flowers are greenish yellow, sometimes tinged red at the base. Secamone glabra from the littoral forest adds a fifth species to this group. It is distinguished by having glabrous corolla tubes. It is most similar to S. toxocarpoides, a fairly often collected species from the far north of the island, including from the Vohémar region. However, S. toxocarpoides is in contrast to S. glabra found at some hundred metres altitude and is not known from the littoral forest. In addition to the glabrous corolla, S. glabra differs from S. toxocarpoides by a narrower corolla tube that in bud gradually narrows into the lobes. In S. toxocarpoides, the buds are subglo-bose at base and more abruptly narrow above the tube into the contorted lobes. The broader corolla tube of S. toxocarpoides also manifests as small pouches protruding between the calyx, and the corolla lobes are distinctly widened at the very base. In S. glabra, the tube does not protrude or only insignificantly protrudes between the calyx lobes and the corolla lobes gradually narrow from the base.
Secamone glabra might also be confused and furthermore shares habitat with S. obovata Decne., a common species found along all of the eastern littoral forest on sand. Secamone glabra differs by dorsiventrally flattened corona lobes (vs falcate lobes in S. obovata) and by its glabrous corolla.
Additional specimen studied — Madagascar: Antsiranana: 40 km N of Vohémar, near N end of Lac Sahaka. Fir. Nosibe, Fkt. Anjiabe, 2002, McPherson 18843 (MO).
Secamone laevis Klack., sp. nov. – Fig. 10.
Holotype: Madagascar, Tulear, Fort Dauphin. Forêt de Sainte Luce nord de Fort Dauphin, 10 m alt., 4 Dec 1994, Civeyrel 1299 (S!).
Diagnosis — Species haec Secamonae glaberrimae foliis ovatis aliquantum coriaceis vel lobis corollae valvatis similis sed differt lobis coronae minutis gynostegium brevioribus et ad nodos colleteris minutis modo, non late vel distincte triangularis.
Description — Suffrutescent twiner with terete, glabrous stems. Leaves opposite, herbaceous but somewhat coriaceous when dry, flat but at least when dry slightly revolute at very margin, glabrous; blade 3–4 × 1–1.5 cm, narrowly ovate, cuneate at base, acute at apex; venation not visible except for midrib when dry; midrib ± flush with upper surface, flush to slightly protruding on lower surface; epidermis smooth on both surfaces; petiole 3–6 mm long. Inflorescences axillary or terminal, shorter than adjacent leaves; cymes mostly dichasial, rather lax and with few flowers; axes 1–5 mm long, glabrous; pedicels 3–7 mm long; bracts c. 0.5 mm long, hairy along margin. Calyx lobes 0.7–1 × 0.7–1 mm, very broadly ovate to orbicular, rounded at apex, glabrous but finely ciliate along margin. Corolla ovoid to broadly ovoid in bud and subacute to rounded at apex, fused for ½–⅔ of its length into a tube, valvate, not twisted, hairy from mouth with hairs becoming longer and retrorse toward base of tube, white to yellow; tube c. 1.3–1.7 mm long; lobes erect to curved outward, 1–1.4 × 1–1.4 mm, triangular, subacute at apex, somewhat papillate at central part toward base inside. Staminal column 1.2–1.4 mm high. Corona lobes small, c. 0.3 mm long (free part), dorsiventrally compressed, slightly shorter than staminal column, truncate at apex; basal part flat, attached along 3/5 of length of stamen. Pollinia ellipsoid, c. 0.15 mm long. Style head protruding above staminal column; apical portion about as long as basal portion, 0.7–0.8 mm long, broadened at apex, entire. Follicles c. 5 × 0.4 cm, almost linear and slightly bent, thin-walled, glabrous, recurved ± 90°. Seeds not seen.
Phenology — Flowering specimens seen from October, December and February, in fruit from August.
Distribution and ecology — Secamone laevis is known from littoral forest at the Malagasy eastern coast. It has been collected on sand at altitudes of 5–8 m.
Remarks — Secamone laevis from the Malagasy eastern coast is in habit similar to S. glaberrima Schum. from the central plateau and S. schatzii Klack. from the Masoala peninsula by the ovate, somewhat coriaceous and glabrous, elliptic leaves with only the midrib visible when dry. Furthermore, all three species have small, white-yellow flowers in inflorescences that adhere to the stem in an axillary position, in contrast to the usual extra-axillary position. Secamone laevis also shares with S. glaberrima corolla lobes with a papillate upper surface. In S. laevis, however, the lobes are thinner and the papillae less prominent (seen only when dry). In S. glaberrima, persistent, broadly triangular stipular colleters with dark apices are present around the stems at the nodes. In S. laevis, these are absent or only small, mostly linear colleters are present. Secamone laevis has minute corona lobes, narrow and distinctly shorter than the gynostegium. In both S. glaberrima and S. schatzii, the corona lobes are broadened toward the apex and as long as to overtopping the gynostegium. Secamone laevis and S. glaberrima have valvate corolla lobes in bud; in S. schatzii the lobes are overlapping. Although the prevailing aestivation is contorted in Secamone in line with Apocynaceae in general, species with valvate or imbricate aestivation are present in different groups of the genus.
Additional specimens studied — Madagascar: Toama-sina: Vohibola, forest N to NNW of Andranokoditra village, N of Lac Ampitabe, 5 m alt., 2003, Lowry & al. 6084 (MO, P); Brickaville, Andranonkoditra, Ankanin’ny nofy. Forêt de Vohibola, 8 m alt., 2003, Rabehevitra & al. 407 (MO). — Toliara: Fort-Dauphin, Sainte Luce, 5 m alt., 2012, Razakamalala & al. 7319 (MO).
Secamone parviflora Klack., sp. nov. – Fig. 11.
Holotype: Madagascar, Antsiranana, Sava reg., Vohémar, Antsirabe-Nord, Antanambaon’Isokitra, forêt de Tsihomanaomby, au sud-est du village Antanambaon’Isokitra, 14°06′S, 50°02″E, 18 Nov 2013, Martial, Rakotonirina & Georges Be 256 (MO!; isotype: TAN).
Diagnosis — Species haec Secamonae humbertii et S. supranervi affinis structura gynostegii umbinibus parvis elongatisque supra basim antherarum instructis autem differt inflorescentiis confertis.
Description — Suffrutescent twiner to scrambling shrub to 3 m high; branches ± spreading to divaricate, glabrous. Leaves opposite, somewhat coriaceous, with flat margin; blade 4–7 × 2–3.5 cm, elliptic to obovate, tapering at base, acuminate at apex, glabrous; venation rather densely pinnate, spreading or divaricate, undivided but looped near margin; midrib impressed in proximal part on upper surface, somewhat raised on lower surface; primary nerves and veinlets somewhat raised on both surfaces; epidermis smooth on both surfaces; petiole 4–5 mm long, glabrous. Inflorescences extra-axillary to terminal on branches, much shorter than adjacent leaves; cymes dense, di- to monochasial, many-flowered, with axes and pedicels spreading to divaricate from each other, glabrous or with some small hairs; axes several, 0.5–1 mm long, ± of same length from base to apex, thick; pedicels 1–1.5 mm long; bracts to 0.5 mm long, broad. Calyx lobes 0.5–0.7 × 0.5–0.7 mm, ± orbicular to very broadly ovate, rounded at apex, glabrous but ciliate along margin. Corolla ovate in outline in bud and rounded at apex, fused into a tube for c. ¾ of its length outside and ⅚ of its length inside, valvate, not twisted, white; tube c. 1.5 mm long, with hairs inside in a triangle below each lobe in middle of tube; lobes ± erect to barely opening, c. 0.5 × 0.5 mm, triangular, rounded to broadly acute at apex, thin, glabrous. Staminal column c. 0.8 mm high. Corona lobes 0.5–0.6 mm long (free part), dorsiventrally compressed with flat back, erect, equalling to slightly longer than staminal column; basal part with 2 distinct pouch-like structures at bases of sclerified margins (anther wings), attached along c. ½ of stamen. Pollinia not seen. Style head projecting above staminal column and corona lobes; apical portion about as long as basal portion, c. 0.5 mm long, broadened at apex, slightly bilobed. Follicles c. 4.5 × 0.2 cm, linear, thin-walled, glabrous, not recurved. Seeds not seen.
Phenology — Flowering specimens seen from November and February, in fruit from November.
Distribution and ecology — Secamone parviflora is known from the northeastern part of Madagascar near Sambava. It has been collected in humid forest on sand at 85 m altitude.
Remarks — This species is similar to Secamone nervosa Klack. from Loko Be in leaf morphology and by its condensed inflorescences, but differs by its much smaller corona lobes, by having only faintly reticulate leaf venation and by the presence of minute pouch-like structures along the anther wings on the filaments, a character present also in other small-flowered species from the Malagasy eastern coast (e.g. in S. humbertii Choux and S. supranervis Klack.; Klackenberg 1992a). Secamone parviflora differs from all small-flowered species with pouch-like structures along the anther wings by its condensed inflorescences.
Additional specimen studied — Madagascar: Antsiranana: Sava reg., Sambava, Anjangoveratra, Amba-vala, forêt de Tsihomanaomby, Antsahakasaka, 85 m alt., 2014, Martial, Rakotonirina & Georges Be 496 (MO).
Secamone toxocarpoides var. incana Klack., var. nov. – Fig. 12.
Holotype: Madagascar, Antsiranana II, Saharenana, Sadjoavato, Forêt de Sahafary, 12°36′18″S, 49°26′35″E, 270 m alt., 26 May 2005, Hong-Wa 200 (MO!; isotypes: CNARP, P!)
Diagnosis — Varietas haec a typo divergens foliis subter valde pubescentibus.
Description — Leaf blade 2.5–3 × c. 1 cm, elliptic to obovate, attenuate at base, obtuse and usually bluntly apiculate at apex, hairy on both surfaces, densely so on lower surface; petiole 3–5 mm long, covered with mostly reddish hairs. Corolla fused for c. ⅙ of its length into a tube, yellow with reddish base, pale when dry; tube c. 1.3 mm long; lobes c. 7.1 × 1.3 mm. Staminal column c. 0.6 mm high. Corona lobes c. 0.6 mm long (free part), dorsally flat, straight, projecting above staminal column. Style head projecting c. 2½ × longer than staminal column; apical portion c. 2½ × longer than basal portion, c. 1.3 mm long. Follicles not seen.
Phenology — Flowering specimen seen from May.
Distribution and ecology — Secamone toxocarpoides var. incana is known only from the type locality in Sahafary, Antsiranana, a dry deciduous forest area. It was found at an altitude of 270 m.
Remarks — In addition to Secamone glabra, described above from the littoral forest north of Vohémar, a specimen representing a sixth taxon in the group of species morphologically close to S. toxocarpoides (see Remarks to S. glabra) has been found that merits recognition as a new variety. This plant was collected near Sadjoavato in Sahafary forest in the very north of Madagascar and is characterized by its lower leaf surfaces being completely covered by a conspicuous, whitish indumentum of appressed hairs. This is in contrast to the smooth leaves of both S. glabra and S. toxocarpoides. Sahafary forest is located within the distribution range of S. toxocarpoides. The area is covered by dry deciduous forest. The new variety, here described as S. toxocarpoides var. incana, has flowers with short and open corolla tubes with five distinct pouches that protrude between the calyx lobes. The buds are obpyriform, almost globose at the base and with a much narrower, cylindric, apical part of contorted corolla lobes. The flowers are yellowish and basally tinged with red (Fig. 12). These are all floral characters shared with S. toxocarpoides. In fact, no morphological character that distinguishes this taxon from S. toxocarpoides other than the dense indumentum has been observed, and var. incana may be considered an ecotype of this species adapted to a locally dry climate.
The staff and curators of the herbaria cited in the text are kindly acknowledged for the loan of plant material, with special thanks to Sigrid Liede (Bayreuth University) and Douglas Stevens (MO) for sorting out all relevant newly collected material from the extensive P and MO collections. I am also grateful to Missouri Botanical Garden (Tropicos) for sharing their images to illustrate the taxa, thanks that of course also extend to the photographers themselves: Patrice Antilahimena, Peter B. Phillipson, David Rabehevitra and Fidy Ratovoson. Emma Hultén (Stockholm) prepared the line drawings. Thanks are also due to David Goyder (K) and an anonymous reviewer for scrutinizing the manuscript.