Allium pycnotrichum Trigas, Kalpoutzakis & Constantinidis, 2017

Trigas, Panayiotis, Kalpoutzakis, Eleftherios & Constantinidis, Theophanis, 2017, Two new Allium (A. sect. Cupanioscordum, Amaryllidaceae) species from Greece, Phytotaxa 297 (2), pp. 179-188 : 183-186

Allium pycnotrichum Trigas, Kalpoutzakis & Constantinidis , sp. nov. ( Fig. 4 )

Allium pycnotrichum is related to A. hirtovaginatum and to A. iatrouinum from which it differs in the following characters: remnants of leaf sheaths on stem covered by densely white-tomentose indumentum consisting of retrorse hairs 0.5–1.2 mm long, outer tepals 5.0– 6.5 mm long, shorter than the inner, anthers purplish-pink, obtuse. Additional differences are presented in Table 1.

Type:— GREECE. Peloponnisos: Mt. Parnon, SW slopes of Megali Tourla peak, close to the ridge of Roussa Petra peak, rocky slopes with sparse Abies cephalonica trees, 1750–1780 m, 37 o 16.435’ N, 22 o 36.731’ E, 1 August 2015, Kalpoutzakis 4750 (holotype, ACA!, isotype, ATHU!).

Bulbs ovoid, clustered, 11–15 × 7–11 mm, with brown, reticulate-fibrous tunics, detached from the base of the bulb, covering the stem up to 2 cm. Stem erect-ascending to erect, flexuous, 7–11 cm tall, covered by the leaf sheaths for 2/3–4/5 of its length. Leaves 2–3, filiform, subcylindrical, 2–12 cm long, densely white-tomentose with retrorse hairs 0.5–1.2 mm long, shorter to slightly longer than the inflorescence. Inflorescence fasciculate, unilateral, with 4–10 flowers on unequal pedicels 4–15 mm long. Spathe 1-valved, longer to shorter than the inflorescence, 7–9-nerved, 10–23 mm long. Perigone cylindrical-campanulate; tepals pink with a darker purplish mid-vein, the outer 5.0–6.5 × 1.5–2.0 mm, oblong to oblong-ovoid, wider at the middle, the inner 6.0–7.0 × 1.0– 1.5 mm, narrowly oblong, wider at the base, shortly and irregularly dentate at the apex, slightly longer than the outer. Stamens included in the perigone; filaments narrowly triangular, two-coloured, lemon yellow at the lower half and white at the upper half, the inner 3.0– 3.5 mm long and the outer 1.8–2.8 mm long, connate below into an annulus ca. 1 mm high; anthers purplish-pink, oblong, obtuse, 0.8 × 0.4 mm. Ovary green, subglobose, smooth, 1 mm in diameter. Style white, 1.0– 1.5 mm long. Capsule trivalved, subglobose, 2.5–3.5 mm in diameter.

Etymology:—The specific epithet ( “ pycnotrichum ”, i.e. with dense hairs) refers to the tomentose sheaths and leaves of the new species.

Karyology:—The type population of A. pycnotrichum from Megali Tourla peak of Mt. Parnon has a diploid/ dysploid chromosome complement with 2n = 14. This count confirms a previous report from the same population ( Tzanoudakis 1983, under the name A. hirtovaginatum ). The chromosome complement consists of six pairs of metacentric chromosomes (m and m/sm types), one of them macrosatellited on its short arm, and one subtelocentric (st) pair also with a satellite on its short arm ( Fig. 5 ). The dysploid members of A. sect. Cupanioscordum in Greece show a remarkable inter- and intra-population variation, mainly in the morphology of the marker statellited chromosomes, which is mostly exhibited by the changes in the position of the centromere and the nucleolar constriction (see Tzanoudakis 1983).

Distribution:— Allium pycnotrichum is distributed οn Mt. Parnon (SE Peloponnisos) ( Fig. 2 ). Two populations have been discovered so far; the first one is located in the summit area of Megali Tourla and the neighbouring Roussa Petra peak, while the second one was found on Rachi Psari peak, ca. 15 km to the south of the first population. The first population extends at the southern part of Megali Tourla peak, the Roussa Petra peak and along the ridge that connects the two of them. On Rachi Psari peak, A. pycnotrichum is distributed mostly SE of the summit area. Similar plants have also been observed on Xerovouna peak of Mt. Taigetos (S Peloponnisos), but no specimens have been collected and their inclusion into A. pycnotrichum needs confirmation.

Habitat and ecology:— Allium pycnotrichum grows on rocky and stony slopes, in rock crevices and at the bottom of large rocks, on limestone, at 1700–1800 m a.s.l. It flowers in July and August. The plants usually grow in small clusters consisting of ca. 2–5 individuals. The species predominately grows above the tree-line, but it reaches the upper limits of Abies cephalonica Loudon (1838: 81) woodland in Megali Tourla peak. The accompanying taxa of A. pycnotrichum include, among others, Abies cephalonica , Juniperus oxycedrus Linnaeus (1753: 1038) , Sideritis clandestina ( Bory & Chaubard 1832: 170) Hayek (1929: 257) subsp. clandestina , Crepis heldreichiana ( Kuntze 1891: 345) Greuter (1975: 326) , Dianthus serratifolius Sm. in Sibthorp & Smith (1809: 287) subsp. abbreviatus (Heldr. in Halácsy 1901: 217) Strid (1986: 179) and Cerastium candidissimum Correns (1909: 171) .

Conservation:—The Megali Tourla-Roussa Petra population is estimated to comprise about 500–1000 individuals, while the Rachi Psari population is estimated to comprise at least 1000 individuals. Thus, the population size of A. pycnotrichum is estimated to at least 2000 mature individuals. The main summit area of Mt Parnon, as well as Rachi Psari peak are grazed by domestic herbivores, especially goats. Although the A. pycnotrichum individuals are not usually consumed by the goats, they are affected by the animal trampling, which often leads to the eradication of the bulbs. According to our field observations, trampling seems to be the most serious threat for the populations of A. pycnotrichum and can cause a severe population decline in the medium term. Both known populations of A. pycnotrichum are distributed within the protected area of the Natura 2000 network “Oros Parnonas” (GR2520006). The involvement of the Management Body of Mount Parnon and Moustos Wetland in the active management of the A. pycnotrichum populations would have a beneficial effect to the conservation status of the species.

Figures

FIGURE 2. Total known distribution of Allium iatrouinum (blue cycle), A. pycnotrichum (red cycle) and A. ritsii (green cycle).

FIGURE 4. Allium pycnotrichum sp. nov. (A) leaf sheaths with dense retrorse hairs, (B) flowering individuals in their natural habitat, (C) inflorescences, (D) flowers, and (E) bulbs with reticulate-fibrous tunics, which cover the lower part of the stem.

FIGURE 5. A metaphase plate of Allium pycnotrichum, 2n = 2x = 14 (scale bar = 10 μm).