Tripogon wightii Hook.f., Fl. Brit.

K., Thoiba, Abstract, A. K. Pradeep & Roem., Tripogon, 2020, A revision of Tripogon (Poaceae: Chloridoideae) in India, Rheedea 30 (3), pp. 325-378 : 372-374

Tripogon wightii Hook.f., Fl. Brit. India 7(22): 286. 1896; C.E.C.Fisch. in Gamble, Fl. Madras 3:

1833. 1934; Bor, Grass. Burma Ceylon India & Pakistan 524. 1960; S.Moulik, Grass. Bam. India 2: 623. 1997; Pull., Fl. Andhra Pradesh 3: 1269. 1997; Kabeer & V.J.Nair, Fl. Tamil Nadu Grass: 182. 2009; Sasidh., Biodiv. Doc. Kerala –Fl. Pl.: 595. 2004. Lectotype (designated by Thoiba & Pradeep, 2018): INDIA, Mysore, Bellary district, 1834. Wight 1793 (K [K000245012 digital image!]).

FiGS. 46 , 47 & 50

Caespitose perennials. Culms 20–35 cm high; stoloniferous or not, nodes glabrous. Leaf sheaths 2.3–4 cm long, linear, ribbed, persistent, inrolled to the culm; ligules indistinct with a tuft of 4–6 mm long hairs at apex; leaf blades 5–15 × 0.2–0.3 cm, equitant, convolute, margins smooth, minutely ciliate adaxially, glabrous abaxially, margins minutely serrulate towards apex, acuminate to attenuate at apex. Racemes 6–15 cm long, solitary, spike-like, slender, with 8–12 spikelets loosely arranged in rachis; rachis stout, flat to triquetrous and serrulate, 3–7 mm long; peduncles 7–11 cm long, glabrous. Spikelets 13–30 × 0.5–0.7 mm (excluding awns), oblong, distant, dorsiventrally flattened, olive to dark green or yellowish, 5–16- flowered, disarticulation of florets from above glumes and in between florets; callus bearded, hairs 1–1.2 mm long; rachilla 1–1.2 mm long, glabrous to scabrid, almost straight, not persistent; lower glumes 3.6–4.8 × 0.5–0.7 mm, oblong-lanceolate, asymmetrical,1-nerved, 1-keeled, keels slightly scabrid, acuminate at apex, uppermost one with 1– 1.3 mm long arista at apex; upper glumes 5–7 × 1– 1.2 mm, elliptic-lanceolate, 1-nerved, 1-keeled, apex dentate, 1-awned, awns 1–1.5 mm long, aristate at sinus; lemmas 4.8–6.2 × 1.4–2 mm, ovate-lanceolate, 2-lobed, lobes acute-acuminate, 1.2–1.5 mm long, 3-nerved, slightly keeled, 1-awned, median awns 6–8 mm long, scabrid, straight to curved at maturity; paleas 2.3–4.2 × 1–1.5 mm, obovate to elliptic, broadly winged, surface pubescent, 2-keeled, ciliate along margins, sharply 2-lobed with a central notch at apex; lodicules 2, 0.3–0.4 mm long, truncate; stamens 3, anthers 1–2 mm long, oblong, filaments 0.3–0.5 mm long, slender, glabrous; ovary 0.3–0.5 × c. 0.25 mm, obovate, styles 0.7–1.2 mm long, slender, hyaline, stigma 1.2–1.3mm long, plumose, creamy white. Caryopses 1.4–2.2 × 0.5 mm, oblong-elliptic, light brown.

Flowering & fruiting: Flowering and fruiting from August to January.

Habitat: Occuring in seasonally wet hill slopes in association with Arundinella ciliata Nees , Tripogon bromoides , T. sivarajanii (all Poaceae ), Cyanotis tuberosa , Murdannia semiteres (both Commelinaceae ) and Henckelia incana ( Gesneriaceae ).

Distribution: Endemic to Peninsular India .

Specimens examined: INDIA , Andhra Pradesh, Chittoor district , Horsleykonda, 08.1989, J . S . Gamble 20920 ( CAL). Kerala, Ernakulam district, Shoolamudi , Variyam, 14.12.2016, Nikhil Krishna & K . Thoiba 146741 ( CALI); Palakkad district , Nelliyampathy, 07.11.2013, K . Thoiba 134490, 146679 ( CALI); Thrissur district, Sholayar , valve house, 11.12.2013, K . Thoiba 138031 ( CALI). Tamil Nadu, Coimbatore district , Valparai, Shivamalai, 13.12.2013, K . Thoiba 138011 ( CALI); Nilgiri district , Pakasuramalai, 29.08.1957, K . M . Sebastine 3944 ( CAL) .

Notes: Tripogon wightii differs from other species in having leaves shorter than racemes, leaf blades equitant, spikelets being large sized (up to 20 mm long), awns in lemma straight when young and recurved at maturity, awns never more than twice as long as the lemma, and palea notched at apex.

Figures

FiG.46. Tripogon wightii Hook.f.in its natural habitat at Nelliyampathy hills in Palakkad distriCt (Photo by K. Thoiba).

FiG.47.Tripogon wightii Hook.f.:a. Habit;b. Spikelet;c.Lower glume; d. Upper glume;e. Lemma; f. Palea;G. LodiCule; h. Stamen;i. Pistil; j. Caryopsis.

FiG.50. Distribution ofTripogon vellarianus Pradeep,T.velliangiriensis Murug.& V.Balas.,T. wightii Hook.f.and T.zeylaniCus Nees ex Steud. in India [drawn using ESRI (2011) ArCGIS Desktop: Release 10].