Scherberich, D. & J.Duruisseau (2016). Begonia henrilaportei Scherber. & J. Duruisseau (Begoniaceae), a new endemic species from the Masoala peninsula, Madagascar. Candollea 71 : 13–18. In English, English and French abstracts. DOI : http://dx.doi.org/10.15553/c2016v711a3
Begonia henrilaportei Scherber. & J. Duruisseau, new species of Begoniaceae from the Masoala peninsula, in north-east Madagascar, is described and illustrated. It is provisionally placed in section Nerviplacentaria A. DC. and compared with Begonia lyallii A. DC. with which it presents morphological affinities. It is also compared with Begonia nana L'Hér. and Begonia bogneri Ziesenh. with which it has been mistaken in herbarium. A comparative table of characters is provided. The new species differs from these three species by having a caulescent habit with a creeping stem and linear-lanceolate blades with pinnate venation. The diagnostic characters, geographic distribution and a preliminary conservation assessment of the new species using the IUCN Red List Categories and Criteria are presented.
Introduction
The genus Begonia L. (Begoniaceae) contains 1,800 recognised species (Hughes et al., 2015) of perennial or occasionally annual herbs, widely distributed in the tropical and subtropical regions, sometimes extending into parts of temperate Asia. In the revision of Begoniaceae for the “Flore de Madagascar et des Comores”, Keraudren-Aymonin (1983) recognised 48 species of Begonia in Madagascar. Since then, only one species of Malagasy Begonia has been described, B. masoalaensis M. Hughes ( Hughes, 2011). With the exception of B. oxyloba Welw. ex Hook. f. which is largely distributed in tropical Africa, and the doubtfully native B. humilis Dryand., all known species are endemic to the island. Most of them are only known from a very restricted area. The introduction into cultivation in the past decade of various species allowed a better understanding of some taxa but also highlighted a few other ones which doesn't seem to correspond to any known species. It is one of these novelties which is here described and illustrated. Living plants were originally introduced into cultivation in 1998 by Henri Laporte, and then again by Jacky Duruisseau in 2009, on a collecting trip which followed the footsteps of Laporte in the Masoala peninsula (Fig. 1).The publication of this new species raises to a total of 50 the number of Begonia species known from Madagascar and to 8 the number of species recorded for the Masoala region. These include B. antongilensis Humbert, B. bogneri Ziesenh, B. erminea L'Hér., B. henrilaportei Scherber. & J. Duruisseau, B. lyallii A. DC., B. masoalaensis, B. nana L'Hér. and B. tsimihety Humbert.
Systematics
Begonia henrilaportei Scherber. & J. Duruisseau, spec. nova (Fig. 2, 3).
Typus: Madagascar. Prov. Toamasina: Masoala Peninsula, Ambanizana, trail along coast 3–6 km S of Ambanizana, 15°39′S 49°58′E, 30.X.1992, fl., Schatz et al. 3370 (holo- : P [P00137297]! ; iso- : MO-2740146!, TAN!, WAG!).
Begonia henrilaportei Scherber & J. Duruisseau differs from all other Malagasy species by the unique combination of creeping stem, linear-lanceolate blades with pinnate venation, male flowers composed of 2 perianth segments and female flowers with 4 segments.
Perennial lithophytic herb ; Stems creeping, to 30 cm long and 3 mm wide, turning woody at the base, branched, pale green to red, sparsely hairy ; internodes 0.5–2.5 cm long. Stipules persistent, narrowly triangular, the margins entire, 0.5–0.9 cm long, pale green to red. Leaves numerous, alternate, straight, simple, to 5–14 cm long; petiole short, 0.5–2.5 cm, green tinted red, sparsely hairy. Blade symmetric to slightly asymmetric, linear-lanceolate, 5–11 × 0.4–1.3 cm, attenuate at the base, the margins strongly incised, 6–10 incisions per side ; adaxial surface pale green, glossy, with white granular inclusions ; abaxial surface paler, semi-glossy, margins tinted red ; midrib raised on adaxial side, convex, darker green, sometimes with a few trichomes on upper part, convex and tainted red on abaxial side ; venation pinnate, with 6–10 veins per side, darker. Inflorescence axillary, monochasial, pauciflowered, bearing 2–5 flowers at summit, generally bisexual, protandrous, the male flowers basal, bearing a solitary female flower distally ; peduncle to 1.5–7.5 cm, pale green, sometimes tinted pink in upper part, bracts early caducous ; bracteoles absent ; perianth bright pink, the segments rounded at apex. Staminate flowers perianth composed of 2 segments, free, suborbicular, 5-7.5 mm × 5–7 mm ; Androecium zygomorphic ; stamens 8–11, fasciculate, free, filaments 1.5–2 mm, white ; anthers 1.3–1.6 mm oblong, emarginate at apex, pale yellow, about nearly as long as filaments, dehiscent with lateral longitudinal slits. Pistillate flowers with perianth composed of (3-)4 segments, free ; ovary 3-winged, with one wing conspicuously larger than the two others, pale green, composed of 3 locules, placentation axillary ; placental branches 2 per locule ; styles 3, free, bifid, white to pale pink, persistent; stigma reniform. Fruit a 3-winged dry capsule, nodding, the wings unequal, main wing about 7 mm long and 10 mm wide, the lateral ones about 2.5 mm long and 8.5 mm wide. Seeds globose-ovoid, about 0.3 mm, tegument reticulate.
Etymology. — This new species is dedicated to Henri Laporte, explorer, keen Begonia grower and collector, who discovered and introduced into cultivation many species from Madagascar. Henri died of severe malaria in December 2001, which he contracted on a trip to Madagascar.
Phenology. — Flowering has been observed from November to March.
Distribution and ecology. — Known only from the type locality, along the path connecting Ambanizana to Ambodiforaha near the sea shore, on the west coast of the Masoala peninsula, in the Analanjirofo region, Madagascar (Fig. 1). Begonia henrilaportei is a lithophytic hygrophilous species, on granitic rocks (gneiss) in streams, growing among mosses, pteridophytes and Melastomataceae, close to the sea.
Conservation status. — The only known location of B. henrilaportei lies in the periphery of the Masoala National Park, along a path that is used everyday by farmers and inhabitants of nearby villages. About 10–20 individuals only have been observed and despite a thorough exploration of the surrounding areas on multiple expeditions, no other population has been found so far. We therefore assigned a preliminary conservation status of “Critically Endangered” [CR C2a(i)] (IUCN, 2012).
Notes. — The only other species from section Nerviplacentaria A. DC. with a long, creeping stem is B. lyallii but that species differs by the ovate-triangular to ovate-elliptic blades with palmate venation. It is also superficially similar to and has been mistaken in herbarium with B. nana and B. bogneri but these species both belong to sect. Erminea A. DC. and differ by the tuberous and acaulescent habit, male flowers composed of 4 perianth segments and female flowers with 5–6 segments.
The type, Schatz et al. 3370, was determined in P [P00137297] as B. nana by G. Aymonin (Fig. 3) and in MO and WAG as B. bogneri by J.J.F. de Wilde. A comparative table with distinguishing features between the new species and the morphologically closely related species is presented in Table 1.
Paratypi. — Madagascar. Prov. Toamasina : Maroantsetra, Ambanizana, along path between Ambanizana-Andranobe, 15°39′19″S 49°57′39″E, 11 m, 25.X.2004, fl., Antilahimena 2970 (MO-6340835, P [P05619948], WAG) ; Andranobe, N to Ambanizana, 15°41′S 49°58″E, 5–10 m, 26.II.1999, fl., McPherson 17693 (MO, TAN) ; S. of Ambanizana, 15°39′S 49°57′E, 15 m, 16.XI.1993, fl., van Nek 2087 (TAN, WAG [WAG0232448, WAG0232449]) ; 4 km au S du village d' Ambanizana, rochers sur le sentier qui relie Ambanizana à Ambodiforaha en longeant la mer, 21.III.2013, fl., Scherberich 969 (L'YJB [LYJB010461, LYJB010462]) [Plante cultivée au Jardin Botanique de Lyon sous le numéro 060667, collectée à l'origine par H. Laporte].
Fig. 1
Distribution of Begonia henrilaportei Scherber. & J. Duruisseau (white stars) in the Masoala Peninsula, Madagascar plotted on a map of forest cover In 2000 (grey) following Harper et al. (2007).
Fig. 2.
Begonia henrilaportei Scherber. & J. Duruisseau. A. Habit in the type locality; B. Leaf adaxial surface; C. Apex of stem; D. Leaf abaxial surface; E. Inflorescence showing female flower and male flower bud; F. Stamens. [Photos: A: J. Duruisseau; B–F: D. Scherberich]
Fig. 3.
Holotype of Begonia henrilaportei Scherber. & J. Duruisseau. [Schatz et al. 3370, P] [© Muséum national d'Histoire naturelle, Paris. Reproduced with permission]
Table 1.
Morphological and ecological features distinguishing Begonia henrilaportei Scherber & J. Durulsseau from B. bogneri Ziesenh., B. lyallii A. DC. and B. nana L–Hér.
Acknowledgements
We wish to thank Evelyne Bouquet who is in charge of the living collection of Begonia at the Jardin Botanique de Lyon, for keeping the plants in cultivation, helping with observations and assistance in locating publications from the Association Française des Amateurs de Begonia. The authors also wish to thank the P herbarium for giving permission to use the scan of the holotype, as well as Marc Hughes from the Royal Botanic Garden Edinburgh and Martin W. Callmander from the Conservatoire et Jardin botaniques de la Ville de Genève for their careful reviews of the original version of this article and their suggested improvements.
