NeBIO I www.nebio.in I September 2019 I 10(3): 168-174 RESEARCH ARTICLE Taxonomy of endemic dwarf grass Oropetium villosulum Stapf ex Bor, an overlooked cohabitant of Oropetium thomaeum (L.f.) Trin. Nagaraju Siddabathula1, Ravi Kiran Arigela1*, Rajeev Kumar Singh2 & P.V. Prasanna1 1Botanical Survey of India, Deccan Regional Centre, Zoological Survey of India Campus, Attapur Village, Hyderabad - 500048, Telangana 2Botanical Survey of India, Southern Regional Centre, TNAU Campus, Lawley Road, Coimbatore - 641003, Tamil Nadu Email: [email protected] ABSTRACT The endemic dwarf grass Oropetium villosulum Stapf ex Bor hitherto known strictly from the Western Ghats of Karnataka and Maharashtra is reported here as an addition to the flora of Telangana based on collections from Ranga Reddy, Vikarabad and Yadadri Bhuvanagiri districts. This species coexists with its closely allied species, O. thomaeum and both species also produce flowers and fruits during the same period. Detailed descriptions and coloured photo plates of dissected microscopic floral parts of these two species are provided here to distinguish them unambiguously. Furthermore, lectotype for the name O. thomaeum (L.f.) Trin. (≡ Nardus thomaea L.f.) is designated. KEYWORDS: Endemic, Hyderabad, lectotype, Poaceae, Telangana, Vikarabad. Introduction different localities, Ananthagiri Hills (Vikarabad district), The members of family Poaceae (with about 740 genera) Ramannapeta (Yadadri Bhuvanagiri district), Tolichowki and constitute one of the most fascinating groups of flowering plants Rajendranagar (Ranga Reddy district). After detailed studies of with wide, ubiquitous distribution and immense diversity. The protologue, relevant literature (Linnaeus filius, 1782; Hooker, genus Oropetium Trin. (subfamily Chloridoideae) consists of 6 1896; Cooke, 1908; Blatter and McCann, 1935; Bor, 1950, 1960; species and is distributed in Africa, Arabian Peninsula, Indian Jain, 1967) and the type specimens (available online), the identity subcontinent to Indo-China (POWO, 2019). In India, so far 3 of these two grasses was ascertained as Oropetium thomaeum species have been reported, namely O. roxburghianum (Schult.) S. (L.f.) Trin. and O. villosulum Stapf ex Bor. These two species in M. Phillips, O. thomaeum (L.f.) Trin. and O. villosulum Stapf ex the above four localities exist together in the same habitat and Bor, of which first and last one are endemic to India. The species their period of phenology is also same. The other associated of Oropetium are generally known as desiccation tolerant grasses, species of these two grasses is Cyanotis fasciculata (B. Heyne ex which grow in gravelly, rocky and sandy areas, and complete the Roth) Schult. & Schult.f. of family Commelinaceae (Fig. 1). flowering and fruiting before moisture evaporates. Detailed description and images of habitat, habit and dissected microscopic floral parts are provided for O. thomaeum and O. During systematic study of grasses of Telangana state, specimens villosulum (Fig. 1–3) to unambiguously distinguish these two of two small grasses were collected in August 2019 from four species. Earlier, Oropetium villosulum is an endemic species, Received 2 September 2019 I Accepted 26 September 2019 I Published online 30 September 2019 Citation: Siddabathula, N., Arigela R.K., Singh, R.K. & P.V. Prasanna. 2019. Taxonomy of endemic dwarf grass Oropetium villosulum Stapf ex Bor, an overlooked cohabitant of Oropetium thomaeum (L.f.) Trin.. NeBIO 10(3): 168-174. Acknowledgement The authors are thankful to the Director, Botanical Survey of India, Kolkata for facilities. We are also grateful to the curators of BM, LD, LINN and K for providing the digital images and information of type specimens. Copyright © Siddabathula et al. 2019. NECEER, Imphal allows unrestricted use, reproduction, and distribution of this article in any medium by adequate credit to the author(s) and the source of publication. NeBIO, An International Journal of Environment and Biodiversity Official publication of North East Centre for Environmental Education (NECEER), Imphal I ISSN 2278-2281 (Online), 0976-3597 (Print) I www.nebio.in Siddabathula et al » Taxonomy of endemic dwarf grass Oropetium villosulum, an overlooked cohabitant of Oropetium thomaeum NeBIO 10(4): 168-174 hitherto known from the Western Ghats of Karnataka and brownish purple. Caryopsis oblong-obovate, 0.8–1 × 0.3–0.4 mm, Maharashtra has neither been recorded from undivided Andhra more or less truncate at apex, narrowed at base, brownish. (Fig. 2) Pradesh state nor from the newly formed Telangana state, hence it is a new record to the flora of Telangana state. Furthermore, Flowering & Fruiting: July–November. lectotype for the name O. thomaeum (L.f.) Trin. is designated here Habitat: Grows in rocky crevices, gravelly, rocky and sandy soils in in accordance with Article 9.3 and recommendations 9A and 9C of plains, dry deciduous forests and on hillocks. the ICN (Turland et al., 2018). Distribution: Northeast and East Tropical Africa, Indian Taxonomy subcontinent to Indo-China. In India, it has been reported from Oropetium thomaeum (L.f.) Trin., Fund. Agrost.: 98, t. 3. 1820; Andhra Pradesh, Bihar, Chhattisgarh, Delhi, Gujarat, Haryana, Hook.f., Fl. Brit. India 7: 366. 1896; T. Cooke, Fl. Bombay 2: 1046. Karnataka, Kerala, Madhya Pradesh, Maharashtra, Odisha, 1908; C.E.C. Fisch. in Gamble, Fl. Madras: 1830. 1934; Blatt. & Punjab, Rajasthan, Tamil Nadu, Telangana, Uttar Pradesh, McCann, Bombay Grasses: 247. 1935; Bor, Grass. Burma, Ceylon, Uttarakhand and West Bengal. India & Pakistan: 474. 1960; S.K. Jain, Bull. Bot. Surv. India 9: 284, f. 2. 1967. Nardus thomaea L.f., Suppl. Pl.: 105. 1782. Notes: In the protologue of Nardus thomaea L.f., the type locality stated by Linnaeus filius was St. Thomas Mount, region Type: “Habitat in Tranquebaria ad Montem Sancti Thomae. König.” Tranquebar (Tharangambadi, Nagapattinam district) and collector Lectotype (designated here): India, Tamil Nadu, Chennai, St. as Koenig, but presently St. Thomas Mount is in Chennai. St. Thomas Mount, 1774, J. G. Koenig s.n. (specimen on left of LINN- Thomas Mount is a small hillock near Chennai International HL73-1, image!, designated here; isolectotypes: BM000959486, Airport. Johann Gerhard Koenig (1728–85) was a surgeon and image!, LD1755530, image!, specimens on the middle and right of studied botany under the father of taxonomy Carl Linnaeus in LINN-HL73-1, image!, LINN-HL73-2, image!) Sweden. He arrive India in 1768 in Tranquebar to take up the position of doctor at the missionary. In 1774 he embarked on a Caespitose annual, 4–11 cm high (including inflorescence); culms voyage to the mountains north of Madras and to Ceylon (Jenson, 2.5–6 cm long, erect, branched; nodes glabrous. Leaf blades 2005) and during this voyage Koenig collected the specimens of filiform or linear, after drying conduplicate, 10–35 × 3–8 mm, apex N. thomaea from St. Thomas Mount. Later in 1782 this grass was acute to shortly acuminate, margins with tubercle-based hairs; described by Linnaeus filius and the species was named after St. ligules oblong, 1–1.3 × 0.3–0.5 mm, truncate, membranous, Thomas. The date of collection 1774 is mentioned on the hyaline; sheaths 5–10 mm long, slightly keeled. Inflorescence a herbarium sheet held at BM (BM000959486). Four herbarium terminal spike, linear-oblong, 20–50 × 1.2–1.6 mm, straight or sheets of N. thomaea collected by J.G. Koenig from India were curved, embraced at the base by a subtending leaf; rachis wavy, traced (BM000959486, LD1755530, LINN-HL73-1 and LINN-HL73- winged, stout, slightly bulgy, scaberulous. Spikelets sessile, 2). The better preserved left hand side specimen of LINN-HL73-1, solitary, sunken, lanceolate, as long as upper glume, embedded in is designated here as the lectotype as it agrees well with the the rachis along both sides, 1-flowered; glumes unequal, protologue. persistent; lower glumes broadly oblong, 0.3–0.4 × 0.1–0.2 mm, apex truncate and irregularly 4 or 5-dentate, membranous, In previous works (Bor, 1960; Yadav, 2012) the lemma was hyaline, nerveless; upper glume lanceolate-oblong, 1.5–2× 0.3– described as glabrous, but the illustration made by J. D. Hooker 0.4 mm, apex acute and finely serrulate, chartaceous to on the specimen K000245052 shows lemma as scaberulous in subcoriaceous, not keeled, unawned, margins thick, basal part of upper part on dorsal surface and during present work also the margin hyaline, 3-nerved; lateral nerves prominent, band-like and same scaberulous lemma seen. thick, middle nerve faint; floret 1, bisexual; floret callus bearded with white villous hairs; hairs upto ¾ths of the lemma length; Oropetium villosulum Stapf ex Bor, Kew Bull. 4: 571. 1950 & lemma obovate, boat-shaped, 1.1–1.5 × 0.5–0.6 mm, apex obtuse Grass. Burma, Ceylon, India & Pakistan: 474. 1960; S.K. Jain, Bull. or mucronulate or slightly emarginate, chartaceous to Bot. Surv. India 9: 284, f. 1. 1967; Lakshmin. in B.D. Sharma et al., membranous, hyaline, dorsally scaberulous at upper part, faintly Fl. Maharashtra Monocot.: 544. 1996; Naik, FI. Marathwada 2: 3-nerved, 1-keeled; keel finely serrulate; palea oblong to slightly 1064. 1998; Potdar et al., Grasses Maharashtra: 498. 2012. obovate, as long as lemma, apex slightly 3 or 4-dentate, membranous, hyaline, 2-nerved, faintly keeled or not; lodicules 2, Holotype: India, Central Provinces (presently Madhya Pradesh), obovate, minute, truncate at apex; stamens 3, inserted, 2 equal in Nimar district, Rocky bed of stream below Humra, 21 Dec. 1888, length and one smaller; anthers 0.17–0.2 mm long, greenish J.F. Duthie 8523 (K000245054, image!). yellow; filaments as long as anthers or slightly longer, hyaline; Paratype: India, Maharashtra, Poona (Pune), Aug. 1832, V. ovary elliptic, as long as anthers, gibbous, brownish; style 2, free, Jacquemont 430 (K000245055, image!). 0.1–0.12 mm long, hyaline; stigma plumose, 0.12–0.15 mm long, 169 ISSN 2278-2281 (Online), 0976-3597 (Print) I www.nebio.in Siddabathula et al » Taxonomy of endemic dwarf grass Oropetium villosulum, an overlooked cohabitant of Oropetium thomaeum NeBIO 10(4): 168-174 Figure 1.