Bogdanović, S., C. Brullo, S. Brullo, G. Giusso del Galdo, C. M. Musarella & C. Salmeri (2011). Allium cithaeronis Bogdanović, C. Brullo, Brullo, Giusso, Musarella & Salmeri (Alliaceae), a new species from Greece. Candollea 66: 377–382. In English, English and French abstracts.
A new species of Allium sect. Scorodon Koch, Allium cithaeronis Bogdanović, C. Brullo, Brullo, Giusso, Musarella & Salmeri, is described and illustrated from Greece. Its chromosome number (2n = 16), karyogram, leaf anatomy, ecology, and taxonomical relationships are examined. For some morphological features, such as exserted stamens from perigon and tuberculate lobes in the upper part of the ovary, it represents a very isolated species within the section Scorodon.
Introduction
During field investigations on the orophilous flora of Greek mountains, a very peculiar population of Allium L. was found on the top of MontKithairon in Boeotia (C Greece). This plant forms dense tufts localized among the dwarf shrub vegetation colonizing the summit plateau (about 1400 m). It is a small geophyte, with superficial clustered bulbs, characterized by short spathe valves, few-flowered and compact umbel, simple and exserted stamens, ovary with visible nectaries. On the basis of these features, this plant can be referred to Allium sect. Scorodon Koch, which is typically represented by species with punctiform or very circumscribed geographical distribution. According to literature (Stearn, 1978, 1980, 1981; Garbari & al., 1979; Miceli & Garbari, 1979; Phitos & Tzanoudakis, 1981; Tzanoudakis, 1983, 1992; Tzanoudakis & Vosa, 1988; Brullo & Tzanoudakis, 1989; Brullo & al., 1992, 1993, 1994, 2001; Tzanoudakis & Kollmann, 1991; Hanelt & al., 1992; Trigas & Tzanoudakis, 2000, Friesen, 2001), this section is represented in Greece by several species, mostly endemic and found in coastal and inner stands. From herbarium and field investigations, the MontKithairon population is morphologically well differentiated from the other ones of Allium sect. Scorodon s.l., hitherto known from Greece. Therefore, it is described as a species new to science.
Material and Methods
The investigation is based on about 40 living flowering bulbs collected on the top of MontKithairon (C Greece) and cultivated in the Botanical Garden of Catania (Italy). The morphological analysis of diacritic characters was made on fresh material; the voucher specimens are deposited in ATH, CAT, G, FI, UPA, and ZA. In addition, several specimens of Allium sp. pl., preserved in many European Herbaria (B, BM, C, CAT, FI, G, HUJ, ISTE, K, M, P, PR, PRC, RO, W, WU, ZA) and belonging to other species of Allium sect. Scorodon, have been examined and compared.
The leaf anatomy was studied on leaf blades of maximum size coming from the living original collection, sectioned using a freezing microtome.
The karyological analyses were made on mitotic plates from root-tip cells of cultivated bulbs, pre-treated with 0.3% colchicine water solution, fixed in ethanol-acetic (3:1) and stained according to the Feulgen technique. Metaphases observations and chromosome measurements were made using the image analysis systems IKAROS 4.6 (Metasystem) and AXIOVISION 5.1 (ZEISS). Karyotyping was done with the software Cromolab© 1.1. (Brullo, 2002–2003) specialized in recognizing chromosome pairs, ordering them by size and classifying by morphology, and assembling the karyotype formula based on the centromere position (Levan & al., 1964; Tzanoudakis, 1983).
Results
Allium cithaeronis Bogdanović, C. Brullo, Brullo, Giusso, Musarella & Salmeri, spec. nova (Fig. 1)
Holotype: GREECE. Sterea Ellas: MontKithairon in stazioni cacuminali a ca. 1400 m. di quota, 38°11 63 N, 23°14 46 E, 3.VII.2007, Brullo, Musarella 50.07 (holo-: CAT; iso-: ATH, CAT, FI, G, UPA, ZA). Bulbus 10–15 × 7–10 mm, tunicis exterioribus coriaceis, brunneis. Scapus 6–11 cm altus. Folia semicylindrica, viridia, 40–60 × 2–2.5 mm. Valvae spathae inaequales, major 1–2.2 cm longa, minor 0.8–1.3 cm longa. Inflorescentia compacta, 6–15 floribus. Tepala elliptica, 4–5 × 1.8–2 mm, albo-rosea, apiculata. Stamina e perigonio exserta, filamentis albidis, subaequalibus, 3.5–4 mm longis, antheris luteopallidis, ca. 1 mm longis. Ovarium subcylindricum, 2.5–3 × 1.4–1.5 mm, superne dilatatum in 6 lobos tuberculatos, tumulis nectariorum bene visillibus. Capsula subglobosa, 3–3.5 mm diametro.
Bulb ovoid, 10–15 × 7–10 mm, with membranaceous whitish inner tunics, the outer ones coriaceous, dark brown. Stem 6–11 cm high, cylindrical, glabrous, erect, covered by the leaf sheaths for 1/2-2/3 of its length. Leaves 4, semicylindrical, glabrous, green, smooth, 4–6 cm long, 2–2.5 mm wide. Spathe persistent, with two valves unequal, subequal or longer than the inflorescence, the larger 6–7-nerved, 1–2.2 cm long, the smaller 3–5-nerved, 0.8–1.3 cm long. Inflorescence compact, 1–2 cm in diameter, 6–15 flowered, with subequal pedicels 4–6 mm long. Perigon campanulate, with equal tepals, whitepinkish tinged with purple, green-purplish midrib, elliptical, apiculate at the apex, 4–5 mm long and 1.8–2 mm wide. Stamens exserted from perigon, with simple white filaments, subequal, 3.5–4 mm long, below connate into an anulus 1 mm high. Anthers pale yellow, elliptical, 1 × 0.8 mm, rounded at the apex. Ovary green-yellowish, subcylindrical broadened at the top in 6 tuberculate lobes, 2.5–3 mm long, 1.4–1.5 mm wide, with basal mounds of nectaries well visible. Style white, 05.– 0.7 mm long. Capsule green, trivalved, subglobose, 3–3.5 mm in diameter, with 6 small ovoid appendages on the top.
Etymology. — The specific epithet refers to “Cithaeron” the old name of MontKithairon in Boeotia (Greece).
Habitat and Distribution. — Allium cithaeronis is localized on the top of MontKithairon (about 1400 m), an isolated mountain near Erythres (C Greece). This species has a flowering peak in June, and it is member of a dwarf shrubby vegetation characterized by many prostrate or caespitose orophytes, such as Thymus parnassicus Halacsy, Crepis incana Sm., Asperula rigidula Halacsy, Cerastium candidissimum Correns, Silene radicosa Boiss. & Heldr., Minuartia attica Vierh., Galium thymifolium Boiss. & Heldr., Nepeta argolica Chaub., Festuca janpertii (St-Yves) Markgr.-Dannen., Anthemis cretica L., Pterocephalus perennis Coult., Achillea holosericea Sibth. & Sm., Paronychia macedonica Chaudhri, etc. This vegetation is extremely peculiar and interesting from the phytogeographical viewpoint. Unfortunately, this vegetation appears nowadays quite degraded, especially for the intensive overgrazing.
Karyology. — Allium cithaeronis is a diploid specie with a somatic chromosome number 2n=16 (Fig. 2A), which is rather common within the genus Allium. The chromosome complement is regular and homogeneous, mostly characterized by metacentric pairs. Only two pairs tend towards the submetacentric type (arm ratio exceeding 1.30) and are indicated as “msm” according to Tzanoudakis (1983). Short satellites were well evident just in few metaphases, occurring on the long arm of one msm pair and on the short arm of the smallest metacentric pair (Fig. 2B). The karyotype formula can be resumed as 2n = 2× = 16: 10 m + 2 msat + 2 msm + 2msmsat. The absolute chromosome length varies from 14.40 ± 1.83 μm for the longest chromosome, to 8.15 ± 1.26 μm for the shortest one, while the relative length ranges from 8.05 ± 0.37% to 4.55 ± 0.17%. Many different indices were also calculated to evaluate the symmetry degree of the chromosome complement; all values remarked a high homogeneity in the karyotype of A. cithaeronis (Table 1).
Leaf anatomy. — The leaf cross section of A. cithaeronis shows a subelliptical outline. The epidermis is covered by a well developed smooth cuticle. The stomata are numerous and distributed along the whole perimeter. The palisade tissue is regular and compact and consists of one-layered cylindrical cells. The spongy tissue is compact or with larger intercellular spaces and bigger cells in the centre. In the peripheral part of the spongy tissue several secretory canals occur. The vascular bundles are 13, of which 7 are abaxial (4 of which bigger) and 6 are adaxial (Fig. 3).
Discussion. — As already stated before, due to some morphological features, mainly regarding spathe valves, stamens and ovary, A. cithaeronis should be included in the A. sect. Scorodon Koch s.l. Several authors (Valsecchi, 1974; Cheshmedzhiev, 1975; Hanelt & al., 1992; Friesen & al., 2006; Brullo & al., 1995, 2008) have already highlighted that this section represents a not natural group, since it includes several taxa morphologically rather heterogeneous. Actually, some species, previously referred to this section, have been recently included in other distinct sections, such as Allium sect. Brevispatha Valsecchi (type: A. parciflorum Viv.), Allium sect. Cupanioscordon Cheshm. (type: A. cupanii Rafin.), Allium sect. Eremoprasum (Kamelin) F. O. Khass., R. M. Fritsch & N. Friesen (type: A. sabulosum Stev.), Allium sect. Avulsea F. O. Khass. (type: A. rubellum M. Bieb.), etc. As concerns Allium sect. Scorodon s. str., it has been attributed to the subgenus Polyprason Radić, while the just mentioned sections belong to the subgenus Allium (see Friesen & al., 2006). Unfortunately, we did not do any molecular analyses on A. chitaeronis, but we deem that, basing on morphological evidences, this species should be, at least for the time being, included in Allium sect. Scorodon s. str. (type: A. moschatum L.). In fact, this section is characterized by spathe valves acuminate or cuspidate, not much developed and usually shorter than umbel, stamen filaments simple or with two short teeth in the lower part and ovary with well visible nectaries. However, A. cithaeronis shows a character rather unusual for the species of this section, such as stamens clearly exserted from the perigon. According to Stearn (1980) and Kollmann (1984), only some Anatolian and Central Asian alliums of this section show this morphological feature: A. microspathum Ekberg, A. wendelboanum Kollmann, A. sabulosum Bunge, and A. sieheanum Kollmann. Many diacritic features regarding size and shape of the stems, leaves, spathe valves, umbels, flowers and capsule allow to well distinguish them from A. cithaeronis. In particular, the ovary of the above mentioned species is always without broadened lobes in the upper part.
Allium cithaeronis shows also some relationships with certain species of the Allium sect. Codonoprasum Reichenb., particularly with those ones belonging to the A. stamineum Boiss. group. These affinities chiefly regard the habit and the stamens exserted from the perigon, but the spathe valves much longer than umbel, and ovary without visible mounds of nectaries allow to distinguish the species of A. stamineum group from A. cithaeronis (Brullo & al., 2007).
Therefore, based on the current knowledge on the genus Allium in Greece, A. cithaeronis can be considered a species taxonomically quite isolated, especially for some morphological characteristics. Moreover, it should be stressed that A. sect. Scorodon s. str. groups many rare species, usually well differentiated and showing an extremely localized distribution, such as A. meteoricum Halácsy, A. maniaticum Brullo & Tzanoud, A. calamarophilon Phitos & Tzanoud., A. lagarophyllum Brullo, Pavone & Tzanoud., A. chalkii Tzanoud. & Kollmann, A. runemarkii Trigas & Tzanoud (Brullo & Pavone, 1983; Tzanoudakis, 1983, 1992; Tzanoudakis & Vosa, 1988; Brullo & Tzanoudakis, 1989; Brullo & al., 1992, 1993, 1994).
Fig. 1
Allium cithaeronis Bogdanović, C. Brullo, Brullo, Giusso, Musarella & Salmeri. A. Habit ; B. Perigons ; C. Open perigon with stamens ; D. Anther ; E. Ovaries; F. Capsules; G. Spathe valves.
[MontKithairon, Brullo & Musarella s.n. (CAT)] [Drawn by Salvatore Brullo]
Fig. 2
Allium cithaeronis Bogdanović, C. Brullo, Brullo, Giusso, Musarella & Salmeri. A. Metaphasic plate (2n = 16) ; B. Karyogram.
Table 1.
Measurements and chromosome classification of Allium cithaeronis.
Acknowledgments
We are very grateful to the curators of the Herbaria B, BM, C, CAT, FI, G, HUJ, ISTE, K, M, P, PR, PRC, RO, W, WU, ZA for loans and help during our visits for material consultation.
