Microstegium fasciculatum

S., Dey, S., Das & Karthigeyan, K., 2021, Microstegium (Poaceae), a new generic record for Andaman & Nicobar Islands, India, Rheedea 31 (2), pp. 68-70 : 68-70

Microstegium fasciculatum (L.) Henrard, Blumea 3(3): 453. 1940. Tripsacum fasciculatum (L.) Raspail, Ann. Sci. Nat. (Paris) 5: 306. 1825. Andropogon fasciculatum L., Sp. Pl. 2: 1047. 1753 (‘fasciculatus’). Lectotype (designated by Cope in Cafferty et al., 2000): Habitat in Indiis, Herb. Linn. No. 1211.27, lower central specimen (LINN). Fig.1

Perennial, mat-forming herbs, rooting from the lower nodes. Culms up to 4 m tall, robust or of moderate build; internodes glabrous, sometimes pubescent; nodes glabrous or bearded. Leaf sheaths bearded, outer margins pilose, mouth glabrous or hairy; ligule membranous, 1–3 mm long, blades linear-lanceolate, 8–30 × 0.5–2 cm, attenuate to slightly rounded at base, pseudopetiole absent, pilose, more densely on ventral surface, acuminate to setaceous at apex. Inflorescence of 3–25 digitate racemes, 5–15 cm long; racemes straight, 4–15 cm long; rachis angular, margins ciliate. Spikelets paired, sessile or pedicelled. Sessile spikelets 2.6– 4.5 × 0.7–0.8 mm, oblong, acute at apex, awned; lower glume elliptic-oblong, 3–4 × 0.5–1 mm, dorsally shallowly grooved, 3–4-nerved, 2-keeled; keels ciliate to hairy towards apex, acute, obtuse or emarginate at apex; upper glume elliptic, 3–4 × 0.6– 0.8 mm, strongly compressed, with 0.2–0.4 mm long bristle at tip, 3-nerved with prominent midnerve and 2 faint lateral nerves, midnerve keeled and scabrid. Florets 2, lower floret present, barren; lower lemma 0.5–0.6 × 0.2–0.3 mm, hyaline, with notched apex; lower palea 2.1–2.5 mm, narrowly oblong, acute; upper lemma glabrous, reduced to hyaline base of the awn 0.2–0.4 (–1) mm, apex rounded to emarginate and continued with the awn; awn 6–12 mm long, geniculate, lower twothird chestnut brown in colour, twisted; upper palea ovate-oblong, 0.8–0.9 × 0.4– 0.5 mm, hyaline, acute at apex. Anthers 3, 1.5–2.5 mm long. Pedicelled spikelets 2.5–2.8 × 0.6–0.7 mm; pedicels 2–2.5 mm long, ciliate; lower glume 2.5–2.8 × 0.6–0.7 mm, keels finely serrulate; upper glume 2.5–2.8 × 0.6– 0.7 mm; upper lemma awn 4–5 mm long; other features similar to sessile spikelet. Caryopsis not seen.

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

Habitat: Open disturbed areas.

Distribution: Africa (West-Central, East Tropical, South Tropical), Bhutan, China, Java, Laos, Lesser Sunda Island, Malaysia, Moluku, Myanmar, Nepal, Philippines, Sri Lanka, Sulawesi, Sumatra, Thailand, Taiwan, Vietnam and India.

Specimens examined: INDIA, Andaman & Nicobar Islands, Andamans, 26.03.1904, C. G . Rogers 172 ( CAL). Andhra Pradesh, Visakhapatnam district , S. E . of Gudem camp, 24.02.1947, V . Narayanaswami & Party 592 ( CAL). Assam, Ahitamo Reserve (15 miles) from Fatimabad T. E., 31.01.1955, M. P . Guha 71 ( CAL); Gowhatti hills, November 1852 ( CAL). Maharashtra, Bombay (Mumbai), Malawani, 13.12.1956, P. C . Nanda 1061 ( CAL). Meghalaya, Garo hills, Dambu, December 1886, C . Mann 1 ( CAL). Nagaland, Kohima, 22.12.1885, C. B . Clarke 41737 ( CAL). Uttarakhand, Dehradun, 2000 ft, October 1892, J. S . Gamble 93946 ( CAL). West Bengal, Darjeeling, 2000 ft, 02.10.1870, C. B . Clarke 12576D ( CAL); Jalpaiguri, Jaldapara National Park, Kodalbashi , 26.11.2013, K . Karthigeyan 61224 ( CAL) .

Acknowledgements

The authors thank the Director, Botanical Survey of India and the Head of Office, Central National Herbarium, Botanical Survey of India for access to facilities and support.

Figures

Fig. 1. Microstegium fasciculatum (L.) Henrard. a. Herbarium specimen (CAL0000027329); b. Spikelet; c. Sessile spikelet; d. Pedicelled spikelet; e. & f. Lower glumes; g. Upper glume; h. Lower lemma; i. Lower palea; j. Upper palea;k. Awn with hyaline upper lemma at base; l. Awn (magnified) showing chestnut brown twisted lower part (from C.G. Rogers 172; photos by S. Dey).