68
Microstegium , a new generic record for Andaman & Nicobar Islands
RHEEDEA
Journal of the Indian Association for Angiosperm Taxonomy
Vol. 31(2): 68–70 (2021)
ISSN: 0971-2313 (Print edition)
ISSN: 2582-2438 (Online edition)
https://dx.doi.org/10.22244/rheedea.2021.31.02.05
Microstegium (Poaceae), a new generic record
for Andaman & Nicobar Islands, India
Dey S.1, Das S.2 & K. Karthigeyan2*
1
2
Department of Botany, Muralidhar Girls’ College, P-411/14, Gariahat Road, Kolkata, West Bengal – 700 029, India
Central National Herbarium, Botanical Survey of India, Botanic Garden P.O., Howrah, West Bengal – 711 103, India
*E-mail: karthigeyan.murthy@gmail.com
Abstract: The genus Microstegium Nees (Poaceae) is
reported for the first time from Andaman & Nicobar
Islands, India based on M. fasciculatum (L.) Henrard.
Microstegium fasciculatum is a common species in
mainland India. A brief description and photo plate are
provided for easy identification.
Keywords: Andropogoneae, Microstegium fasciculatum,
Taxonomy.
Introduction
Microstegium Nees (Poaceae, Andropogoneae)
comprises c. 25 species (Clayton et al., 2018) in
the world, distributed in tropical and subtropical
Africa, Asia, Australia and some Pacific islands
(Clayton & Renvoize, 1986; Koyama, 1987;
Watson & Dallwitz, 1992; Hsu, 2000). Chen et al.
(2012), however, mentioned that Microstegium s.str.
is represented by 16 species and one variety
globally. Sur (1985) reported seven species and one
variety while Karthikeyan et al. (1989) and Kellogg
et al. (2020) enumerated eight species from India.
During identification of different taxa in
Microstegium, the authors came across five sheets
of this genus at CAL, collected from Andaman
Islands (probably South Andaman) by C.G. Rogers
during March 1904. After critical study and careful
scrutiny of literature (Rao, 1986; Matthew, 1998;
Pandey & Diwakar, 2008; Murugan et al., 2016)
it is identified as M. fasciculatum (L.) Henrard,
which is not yet reported from Andaman &
Received: 17.09.2020; Revised & Accepted: 25.04.2021
Published Online: 30.06.2021
Nicobar Islands and hence constitute a new
distributional record at genus level.
Taxonomic Treatment
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
Dey et al.
69
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).
70
Microstegium , a new generic record for Andaman & Nicobar Islands
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.
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Kaliyamurthy Karthigeyan