Fimbristylis agasthyamalaensis Viji & Preetha, 2018

Viji, A. R. & Preetha, T. S., 2018, A New Species of Fimbristylis (Cyperaceae) from Western Ghats, India, Phytotaxa 345 (1), pp. 68-72 : 68-71

Fimbristylis agasthyamalaensis Viji & Preetha , sp. nov. ( Fig. 1 )

Type:— INDIA. Kerala: Thiruvananthapuram Distr., Ponmudi , 08°46´20.5´´N & 77°06´21.7´´E, ± 793 m, 27 December 2016, A. R. Viji 5005 (holotype TBGT!; isotypes UCT!, MH!) .

Annual herbs. Roots fibrous. Culms tufted, slightly curved, ribbed, 3–8 × 0.02–0.05 cm, antrorsely scabrid at the margins near apex. Leaves basal, lower ones reduced to sheaths, upper bladed; sheaths membranous, striate; ligule absent; blades linear, recurved, 2–6 cm long, 0.5–1.5 mm wide, sub-acute at apex, antrorsely spinulose-scabrid on the margins. Inflorescence simple, loose, 1–3 spikelets, 1.8–2 × 1–2 cm; involucral bracts 1–3, glume-like, triangular, 2–3 mm long, base dilated, apex acuminate; primary rays slender, glabrous, filiform, angular in cross-section, ca. 0.5 cm long. Spikelets solitary, slightly twisted, linear-lanceolate, 6–12 × 1–1.5 mm, 10–20 flowered, stramineous; rachilla winged, wings persistent; lowermost glume sterile; basal glumes sub distichous, upper glumes distichous, triangularovate, 2.5–3 × 1–1.5 mm, apex acute, stramineous, keeled on back; keel greenish, densely ciliolate at centre; sides nerveless, glabrous, margins hyaline. Stamens 3; filaments 0.2–0.3 mm; anthers oblong, 1–1.2 mm long, short crest on apex. Ovary obovoid, 0.3–0.5 mm long; style triquetrous, ca. 2 mm long, glabrous, pyramidal at base; stigmas 3, 0.8–1 mm long. Nutlet trigonous, obconical, 0.5–0.75 × 0.2–0.5 mm, brownish, verruculose; stipe cupular, yellowish (lighter than body of nutlet); epidermal cells hexagonal.

Comparison:—The diagnostic differences between F. onchnidiocarpa and F. agasthyamalaensis are detailed in Table 1.

Distribution and Ecology:— India, Kerala, Thiruvananthapuram District, Ponmudi hills, forming part of the Agasthyamala Biosphere Reserve (8°13’– 8°58’N and 76°52’– 77°34’E). It falls within the Indo-Malayan realm and the Western Ghats biogeographic zone. The reserve is in the southern end of the Western Ghats, covering an area of over 3500.36 km 2. The reserve hosts one of the most diverse ecosystems in peninsular India and is known as one of the important ‘Hot Spots’ in the Western Ghats. Fimbristylis agasthyamalaensis grows at an elevation of ± 793 m in open grasslands. It is usually localized on marshy areas ( Fig. 2 ). The new species is a member of an annual plant community consisting of Fuirena ponmudiensis Ravi & Anil Kumar (1994: 102) , F. umbellata Rottbøll (1773: 70) , Pycreus flavidus ( Retzius 1788: 13) Koyama (1976: 313) , Exacum sessile Linnaeus (1753: 112) , Eragrostis unioloides ( Retzius 1788: 19) Nees ex Steudel (1855: 264) etc.

Etymology:— The specific epithet, “ agasthyamalaensis ” denotes the Agasthyamala Biosphere Reserve where the type locality, Ponmudi, is located.

Phenology:— Flowering and fruiting was observed from October to March.

Conservation Status:— The new species has been found in one location. Area of Occupancy (AOO) is about 2 km 2. The number of individuals observed is less than 50. The population is highly prone to wild gracing. Besides, being a tourism area and within the perimeter of a deity, it is subjected to severe anthropogenic pressures, and hence the species may be prone to a progressive deterioration of its populations. According to the IUCN criteria ( IUCN 2012a & b, 2016), we recommend a preliminary conservation assessment as Critically Endangered [CR B1ab(iii, v) + 2 ab(iii, v); D].

Note:— Of the known Indian Fimbristylis species, F. agasthyamalaensis resembles F. narayanii Fischer (1931: 46) in its general appearance. However, it is quite distinct in having twisted spikelet (vs. not twisted spikelet), subdistichous glumes densely ciliolate at centre (vs. distichous glumes not ciliolate at centre), 1.2 mm long anthers (vs. 0.6 mm long anthers) and, obconical brownish nut with hexagonal cells having cupular stipe (vs. obovoid whitish nut with depressed apex and raised shoulders with isodiametric cells having non cupular stipe) apart from its smaller habit.

Figures

FIGURE 1. Fimbristylis agasthyamalaensis sp. nov. A. Habit, B. Inflorescence, C–D. Spikelet, E. Spikelet showing rachilla, F. Sterile glume, G. Fertile glume, G1. Densely ciliolate center portion of fertile glume, H. Pistil and stamens when young, I–J. Stamens, K. Nutlets (Photos from A. R. Viji 5005).

FIGURE 2. Fimbristylis agasthyamalaensis sp. nov. A. Habitat, B. Distribution map.