Diagnosis:— Calamagrostis nandadeviensis differs from C. lahulensis by its ligules 6.1–7.8 mm long (vs. 1.0– 5.1 mm long), panicle effuse (vs. congested), callus hairs 1.0– 2.6 mm long (vs. 0.8–1.2 mm long) and, from Calamagrostis scabrescens by its short, weakly geniculate awn, hardly exerted from spikelets and 2.6–4.5 mm long (vs. long, geniculate, exerted from spikelet and 4.5–7.7 mm long), however, differs from them by having palea apically deeply cleft (vs. almost entire) and lodicules fused in lower half (vs. not fused).
Type:— INDIA. Uttarakhand, Chamoli, Nanda Devi Biosphere Reserve, Valley of Flowers National Park, 30.705541N, 79.602266E, 3438 m, 23 August 2019, P. Agnihotri, D. Prasad, S. Jaiswal & R. Yadav 326632 (holotype LWG! isotype BSD!).
Perennial, woody root stocks, sub-densely tufted grass, 50–60 cm tall. Culms erect, 40–55 cm long, innovation intravaginal, geniculate, scabrous, 2–3 nodes below the panicle. Node glabrous, compressed. Leaf sheath splitoverlapping, closed, scabrid on vein; lower leaf sheaths papery; upper leaf sheaths 15–16 cm long. Leaf blade 8.0–15 × 0.3–0.5 cm, lanceolate-linear, flat or involute, scaberulous on adaxial and abaxial surface; apex acuminate; margin scabrid. Ligules 6.1–7.8 mm long, membranous, abaxial surface scabrous, adaxial surface glabrous. Inflorescence a panicle, 7.0–12 × 1.5–2.0 cm, lanceolate, effuse, open, branched; lower branches in whorls of 2–7, ascending, 2–3 cm long, scabrid. Rachis slender, scabrous. Spikelet 5.2–6.0 × 1.2–1.5 mm, pedicellate, lanceolate, laterally compressed, bearing 1-floret and bare rachilla extension, disarticulating above the glume, purple; glumes subequal, floret hermaphrodite. Pedicel shorter than spikelet, scabrous. Lower glume 5.2–6.0 × 1.1–1.2 mm, 1-keeled, 1-nerved, narrowly lanceolate, navicular, purple, scaberulous; apex acuminate; margin scabrid on upper half; keel scabrid. Upper glume 5.0–5.8 × 1.1–1.3 mm, 1-keeled, 3-nerved, narrowly lanceolate, navicular, purple; apex acuminate; margin ciliate on upper half; keel scabrid. Callus hairs 1.0– 2.6 mm long, shorter than half of the lemma. Lemma 3.8–4.9 × 1.3–1.7 mm, 5-nerved, elliptic, navicular, scabrous on upper 3/4 th, 2–4 toothed, awned; apex acute, hyaline, lateral mucro 0.4–0.7 mm long; margin membranous. Awns 2.6–4.5 mm long, slender, scabrous, inserted nearly at middle of lemma. Rachilla 1.5–2.1 mm long; penicillate hairs 2.3–3.2 mm long. Palea 3.1–3.7 mm, 2-keeled, lanceolate, hyaline, deeply bifid; apex acute; ratio of palea to lemma 0.76–0.82 mm. Stamens 3; anther 1.7–2.1 mm long. Lodicules-2, fused on lower half, ovate, apex truncate, 0.6–0.8 × 0.23–0.24 mm.
Flowering and fruiting:— July to September.
Distribution, habitat and biotic association:— Calamagrostis nandadeviensis is known from two localities, the type locality, Valley of Flowers National Park, one of the core zones of Nanda Devi Biosphere Reserve, and in alpine meadows around the Rohtang Pass (Fig. 3). In both the localities, C. nandadeviensis was found growing associated with Briza media Linnaeus (1753: 70), Bromus catharictus Vahl (1791: 22), Dactylis glomerata Linnaeus (1753: 71), Festuca ovina Linnaeus (1753: 73) and Poa alpina Linnaeus (1753: 67) at an elevation ranging from 3400 m to 3700 m in alpine meadows. The Valley of Flowers National Park, Uttarakhand is well known for plant diversity and endemism. About 28 species of grasses have been reported in this region (Bisht et al. 2018). On the other hand, Rohtang Pass is a high mountain pass situated on the eastern Pir Panjal Range of the Himalayas at about 51 km from Manali in Himachal Pradesh. It demarcates Kullu valley from Lahaul Spiti valley in Himachal Pradesh. These regions are characterized by large range of alpine meadows, an open habitat in which grass and non-woody plants are predominately present. As the Valley of Flowers National Park is a protected area, so vegetation of this place is intact from external anthropogenic pressure whereas, Rohtang Pass is an unprotected area, open for tourists and local people, which render its vegetation threatened. Plants growing in this region face anthropogenic threats cause due to overgrazing by animals, increased tourism, etc., and hence the plant diversity is at a risk of extinction in the future.
Etymology:— The species is named after its type locality Nanda Devi Biosphere Reserve.
Taxonomic notes and remarks:— Calamagrostis nandadeviensis is closely allied to C. lahulensis and C. scabrescens, distributed in Himalayan Region and, often similar to C. nagarum (Bor) G. Singh (1984: 94), known only from north-east India (Bor 1960, Kellogg et al. 2020) and two other species known only from China and Myanmar, C. himalaica (Liou ex Chen) Paszko (2015: 142) and C. nyinghchinesis (P. C. Kuo & S. L. Lu) Paszko (2016: 51), which are collectively recognized by similar length of spikelet, more or less scabrid glume and geniculate awns inserted nearly at the middle or above the middle of the dorsal surface of the lemma (Bor 1960, Noltie 2000, Lu & Philips 2006, Paszko 2014). C. nandadeviensis differs from C. lahulensis and C. scabrescens in circumscriptions of habit, leaf blade, ligule, panicle and spikelet (Table 1. Fig. 4.), whereas clearly distinguishable from C. nagarum by having leaf blade 8–15 cm long (vs. 15–30 cm long), ligule 6.1–7.8 mm long (vs. 1–2 mm long) and panicle 7–12 cm long, lanceolate (vs. 12–20 cm long, ovate) (Shukla 1996). However, C. himalaica is recognized by spikelet occasionally bearing 2- florets and awn 4.5–10 mm long, which is conspicuously exerted from spikelet (Paszko 2014) and C. nyinghchinesis by shorter length of anther, that is 0.7–1.1 mm long (Paszko 2016), therefore, C. nandadeviensis is clearly distinct from them.
Additional specimens examined:— Calamagrostis nandadeviensis sp. nov. (paratype): INDIA. Himachal Pradesh, Kullu, Manali, on the way to Rohtang pass, near Maharishi Vedvyas temple, 32.359364N, 77.230075E, 3673 m, 5 August 2019, D. Prasad & R. Yadav 316275, (LWG!).
Calamagrostis lahulensis: INDIA. Himachal Pradesh: Kullu, Manali, 10 km before Rohtang Pass, 32.35789N, 77.21695E, 3635 m, 5August 2019, D. Prasad & R. Yadav 316250, 326868, (LWG!); Marhi, 32.348869N, 77.223234E, 3372 m, 7 August 2019, D. Prasad & R. Yadav 326811, 326814 (LWG!).
Calamagrostis scabrescens: INDIA. Jammu & Kashmir: Kashmir, Sonsal Nullah, Liddar Valley, 3962–4267 m, 31 July 1893, J.D. Hooker 13349, (DD!); Kashmir, Anantnag, Liddar Valley, 3350–3660 m, 22 July 1892, J.D. Hooker 12220 (DD!); Kashmir, Campus of University of Kashmir, 34.051208°N, 74.051208°E, 2662 m, 22 July 2019, S Tripathi, R Yadav & S Jaiswal 316841, (LWG!). Himachal Pradesh: Kullu, Manali, on the way to Marhi, 32.356538N, 77.222545E, 3528 m, 7 August 2019, D. Prasad, R. Yadav 314813, (LWG!). Uttarakhand: Chamoli, Nandadevi Biosphere Reserve, Valley of Flowers National Park, 30.712096N, 79.592776E, 3417 m, 23 August 2019, P. Agnihotri, D. Prasad, R. Yadav & S. Jaiswal 326763, 326762 (LWG!).
Table 1. Comparison of morphological characters (states or ranges) of Calamagrostis lahulensis, C. scabrescens and C. nandadeviensis sp. nov.