Taxonomic Treatment
Fimbristylis pachmarhiensis Mujaffar, A.P. Tiwari & R.L.S. Sikarwar sp. nov. (Fig 1 & 2)
Diagnosis: Fimbristylis pachmarhiensis, is closely similar to F. aestivalis (Retz.) Vahl, by the hairy nature of the plant but differs from it in having few, slender culms (vs. densely tufted culms), inflorescence simple to compound, very loose, bearing 10–20 spikelets (vs. inflorescence decompounds corymb, loose, bearing numerous spikelets), spikelets terete, 8-14-flowered (vs. angular, to 40-flowered spikelets), glume distichous or lower 2 or 3 spiral, 3-nerved (vs. all glume spiral, nerveless), style triquetrous, pubescent throughout (vs. style flat, ciliate towards the top) and achenes obovate, 3.0–5.0 × 2.5–3.0 mm, sparsely tuberculate, apex depressed (vs. achene obovate-elliptic, 0.5–0.8 × 0.2–0.3 mm, brownish, smooth, apex rounded). The new species also shows resemblance with F. griffithii Boeckeler in its eligulate leaf and biconvexed achenes. However, it is quite distinct in having hairy nature of plant (vs. glabrous nature of plant), inflorescence simple to compound, very loose, 4–6 cm long, bearing 10–20 spikelets (vs. inflorescence decompounds corymb, loose, 4–10 long, bearing 70–90 spikelets), spikelets terete, 8-14-flowered (vs. spikelets angular, 6–19-flowered), glume distichous or lower 2 or 3 spiral, 3-nerved (vs. all glume spiral, nerveless), style triquetrous, pubescent throughout (vs. flat, glabrous throughout) and achenes sparsely tuberculate, depressed at apex (vs. smooth, rounded at apex).
Type: India, Madhya Pradesh: Hoshangabad district, Pachmarhi Biosphere Resereve, Panarpani area (22°25’24.”N; 77° 22’ 56”E), 750 m, 17 November 2015, Mujaffar & Tiwari 2514 (holotype CAL!, isotypes BSA!).
Description: Annual herb, 10–25 cm tall, with fibrous roots. Culms slender, trigonous, glabrous or pubscent at the top. Leaves mostly basal, shorter than culm; sheath brown, 1–4 cm long, pubescent, obliquely truncate at apex; ligule absent; leaf blade 10–20 cm long, 0.5–0.7 mm wide, pubescent on both surfaces, margin sometimes slightly involute. Inflorescence simple to compound, large, 4–6 × 2–5 cm, loosely, bearing 10–20 spikelets; involucral bracts 2–5, foliar, 10 cm long, lowest 2-3 leafy, shorter than inflorescence, brownish, pubescent; rays 3–8, primary rays, slender, pubescent, filiform. Spikelets solitary, terete, oblong, elliptic to lanceolate, 3-4 × 0.5–1.0 mm, acute at apex, yellow to brownish, 8-14-flowered; rhachilla narrowed, winged, brownish. Glumes membranous, distichous or lower 2 or 3 spiral, oblong-ovate, 1.5–2 × 1–1.3 mm, acute at apex, glabrous (lower 2 or 3 puberulent), keeled with the prominent midvein excurrent into a mucro, 3-nerved, hyaline towards margins. Stamen 1 or 2; anther oblong-linear, 0.3-0.4 mm long, brownish, apiculate, spurred at base; filament 1-1.2 mm long, hyaline. Style slender, triquetrous, pubescent throughout, dilated at base 0.8–1 mm long; stigma 2, hairy, shorter than style, exserted,c . 0.5 mm long, recurved. Achenes whitish or brownish, biconvex, obovate, 0.8–1 × 0.5–0.6 mm, narrowed towards base with shortly stipitate, depressed at apex, apiculate, sparsely tuberculate, shining, surfaces of achenes reticulate, hexagonal or elliptic to rectangular epidermal cells.
Etymology: The specific name of this species is derived from its type locality, which is the Pachmarhi Hills situated in the state of Madhya Pradesh, India.
Phenology: The phenological period for this species occurs between September and November.
Habitat and Associated species: This species is found in forests on rocky areas at elevations ranging from 528 to 609 m. It grows alongside associated species such as Bulbostylis barbata (Rottb.) C.B. Clarke, Cyperus castaneus Willd., Cyanotis fasciculata (B.Heyne ex Roth) Schult. & Schult.f., and Oropetium thomaeum (L.f.) Trin.
Distribution: This species is known only from a single locality of Pachmarhi Biosphere Resereve, Hoshangabad district in Madhya Pradesh (Central India).
Conservation status : Based on the available information, this plant has been tentatively classified as Data Deficient (DD) in accordance with the IUCN Red List Categories and criteria (IUCN, 2017). The existing data is insufficient to evaluate the risk factor associated with this species. Currently, the plant is known solely from its type locality. To comprehensively assess its distribution, population numbers, subpopulation numbers, the count of mature individuals across its entire range, and the percentage of population decline in recent years, further investigations are required in similar habitats adjacent to the known areas.
Taxonomic note : Fimbristylis pachmarhiensis closely resembles F. aestivalis (Retz.) Vahl due to its hairy characteristics. However, there are several distinguishing characteristics that set it apart. Firstly, F. pachmarhiensis has fewer slender culms compared to F. aestivalis , which has densely tufted culms. The inflorescence of F. pachmarhiensis is simple to compound and very loose, bearing 10-20 spikelets, whereas F. aestivalis has decompound corymbs that are loose and bear numerous spikelets. In terms of spikelet morphology, F. pachmarhiensis has terete spikelets with 8-14 flowers, while F. aestivalis has angular spikelets with up to 40 flowers. Another distinguishing feature is the arrangement of the glumes: F. pachmarhiensis has glumes that are distichous or the lower 2 or 3 are spiral and 3-nerved, while in F. aestivalis, all the glumes are spiral and nerveless. The style ofF. pachmarhiensis is triquetrous and pubescent throughout, while F. aestivalis has a flat style that is ciliate towards the top. Additionally, the achenes of F. pachmarhiensis are obovate, measuring 3.0–5.0 × 2.5–3.0 mm, sparsely tuberculate, and have a depressed apex. In contrast, F. aestivalis has obovate-elliptic achenes that are much smaller, measuring 0.5–0.8 × 0.2–0.3 mm.F. aestivalis achenes are brownish, smooth, and have a rounded apex.
While F. pachmarhiensis shares some similarities with F. griffithii Boeckeler, such as the eligulate leaf and biconvexed achenes, there are distinct differences as well. F. pachmarhiensis exhibits a hairy nature, while F. griffithii is glabrous. Additionally, the inflorescence of F. pachmarhiensis is simple to compound, very loose, and measures 4–6 cm in length, bearing 10–20 spikelets. On the other hand, F. griffithii has a decompound corymb inflorescence that is loose and measures 4–10 cm, bearing 70–90 spikelets. The spikelets of F. pachmarhiensis are terete and 8-14-flowered, while those of F. griffithii are angular and 6–19-flowered. Furthermore, F. pachmarhiensis has distichous or lower 2 or 3 spiral, 3-nerved glumes, a triquetrous and pubescent style throughout, and sparsely tuberculate achenes with a depressed apex. In contrast, F. griffithii has all glumes spiral and nerveless, a flat style that is glabrous throughout, and achenes that are smooth and rounded at the apex.
Table 1 The key diagnostic characteristics to distinguishingFimbristylis aestivalis , F. pachmarhiensis , andF. griffithii .