Sporobolus tetragonus Bor, Kew Bull.

J., Swamy & Arumugam, S., 2021, Sporobolus tetragonus (Poaceae: Chloridoideae), an addition to the flora of South India, Rheedea 31 (4), pp. 296-299 : 296-298

publication ID

https://doi.org/10.22244/rheedea.2021.31.04.06

persistent identifier

https://treatment.plazi.org/id/E51E87EF-7A60-D60A-109B-FC7C0592FA93

treatment provided by

Felipe

scientific name

Sporobolus tetragonus Bor, Kew Bull.
status

 

Sporobolus tetragonus Bor, Kew Bull. View in CoL 4(2): 251.1949, Grasses Burma, Ceylon, India & Pakistan 633.1960. Lectotype (designated by Arumugam et al., 2018): SIAM [ THAILAND], Kanburi , 19.10.1930, A.F.G. Kerr 19762 (K [ K000290399 digital image!]; isolecto (K [ K000290400 digital image!]). Fig. 1 View Fig

Annuals. Culms erect, 35–60 cm high; nodes c. 0.25 × 1.04 mm, glabrous; internodes 2–7 cm long. Leaf blades linear-lanceolate, 2–11 × 0.4–0.6 cm, flaccid, surface rough on both sides, scabrous at margins with tuberculate-ciliate hairs, apex acuminate, base rounded, hairy; ligule with a fringe of hairs, c. 0.76 × 1.25 mm; leaf sheaths 1–5.5 × 0.4–0.7 cm, glabrous, upper ones tightly clasping, lower loose. Inflorescence an open panicle, elliptic, effuse, 8–25 × 2.5–8 cm; primary branches whorled at most nodes and re-branched above the middle nodes, 2– 4 cm long; branches smooth or scaberulous; peduncle terete, 6–24 cm long; pedicels 1–1.5 mm long, scaberulous. Spikelets solitary, lanceolate, 1.14–1.5 × 0.57–0.8 mm, pale green. Glumes deciduous, unequal, reaching apex of the florets; lower glume lanceolate, hyaline, 0.9–1.0 × 0.20– 0.28 mm long, 1/2 of the upper glume, nerveless, without keels, apex acute, scabrous, rough; upper glume elliptic, membranous, 1.33–1.6 × 0.47–0.7 mm, 1-nerved, keeled, apex acute, rough, scabrous above. Lemma elliptic, membranous, 1.23–1.6 × 0.4–0.5 mm, 1-nerved, without keel, apex obtuse or acute, scabrous on upper third part. Palea 0.9– 1.4 × 0.4–0.5 mm, membranous, apex acute, 2- veined. Stamens 3; anthers linear, c. 0.35 mm long, yellowish; filaments c. 0.2 mm long. Ovary elliptic, c. 0.2 mm long, yellowish green; style c. 0.18 mm long, pale greenish; stigma plumose, c. 0.5 mm long, pale greenish. Caryopsis ellipsoid, brownish, 0.67– 0.8 × 0.39–0.46 mm, quadrangular with free soft pericarp.

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

Habitat: Occasional in open areas of dry deciduous forests. It grows in association with Adenosma indiana (Lour.) Merr. ( Plantaginaceae ), Mitracarpus hirtus (L.) DC. ( Rubiaceae ), and Osbeckia zeylanica L.f. ( Melastomataceae ).

Distribution: India, Myanmar, and Thailand.

Specimens examined: INDIA, Bihar, Monger, September 1811, Wallich 3764 ( Wallich cat. No 8883 IDC, microfiche at MH) . Jharkhand, Chota Nagpore, Ramghur ghat, 19.10.1883, C. B . Clarke 33908 ( CAL) . Telangana, Bhadradi Kothagudem district, Kinnerasani Wildlife Sanctuary , Allapally Range, Venkatapuram section, Yerragutta Beat, N 17 ̊51'37.008'', E 80 ̊33'55.583'', 208 m. a.s.l., 30.09.2019, J . Swamy 009805 ( BSID) . Uttarakhand, Jim Corbett National Park , 11.11.1970, P. C . Pant 43141 ( BSD) .

Conservation status: The species is recorded from four states in India. The field observations in Telangana state revealed that the population had about 50 mature individuals within a 100 m 2 (AOO) area in open grasslands. Forest dwellers of the area bring their cattle for grazing in this area, which is one of the major threats to the species. As this grass species is at present known from only a small patch in the Kinnerasani Wildlife Sanctuary in the Eastern Ghats region, it is threatened at the regional level. With less than five localities the species may be regarded as endangered (E), although the extent of occurrence is extensive. Since the situations of the known localities in other states and its presence in the intervening states is unclear, the species should be categorised at present as data deficient (DD) in India ( IUCN, 2019).

Notes: Sporobolus tetragonus is often misidentified by many taxonomists with its closely allied species, S. capillaris Miq. , S. coromandelianus (Retz.) Kunth , and S. ioclados (Nees ex Trin.) Nees , due to the nature of the inflorescences, small spikelets and minute caryopses. A key has been provided here to facilitate their easy identification. The authors have thoroughly checked Sporobolus specimens in various Indian herbaria (BSA, BSID, CAL, HY, KU and MH) and found that some of the specimens of S. capillaris , S. coromandelianus and S. ioclados were wrongly identified as Sporobolus tetragonus . The latter species was last collected from India by P.C. Pant in 1970 from the Jim Corbett National Park, Uttarakhand. The present collection from the Eastern Ghats region represents a rediscovery of the species after a lapse of over 50 years. Besides, very few specimens of this species are available at Indian herbaria, clearly. Hence, this rare grass species only after its precise conservation status has been ascertained.

MH

Naturhistorisches Museum, Basel

C

University of Copenhagen

B

Botanischer Garten und Botanisches Museum Berlin-Dahlem, Zentraleinrichtung der Freien Universitaet

CAL

Botanical Survey of India

J

University of the Witwatersrand

BSID

Botanical Survey of India

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

BSD

Botanical Survey of India, Northern Regional Centre

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Poales

Family

Poaceae

Genus

Sporobolus

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