Calamus himalayanus S. Mondal, S. K. Basu & M. Chowdhury, 2025

Calamus himalayanus S. Mondal, S. K. Basu & M. Chowdhury sp. nov. Fig s. 1–2 View Fig View Fig

Similar to Calamus flagellum Griff. ex Walp. but can be clearly distinguished by shorter habit (up to 13 m long vs c. 30 m long), thicker stem with sheath (6–12 cm diam. vs 2.1– 5.9 cm diam.), single type of flat spines on leaf sheath, ocrea surface without spines, conspicuous glabrous knee, much longer flagellate inflorescences (8–9.5 m long vs 5–6.5 m long), smaller fruits (12–16 × 7–9 mm vs c. 30 × c. 22 mm), and number of vertical scale rows on fruits (15 vs 12).

Type: INDIA, West Bengal, Darjeeling district, Choklong forest, hill slopes of the Mahananda

WLS outskirts, 26°51 ’ 43 ” N, 88°21 ’ 42 ” E, 320 m,

08.02.2020, Mondal & Chowdhury 0184 (holo NBU!;

iso CAL!, CUH!).

Climbing, clustering rattans up to 13 m tall; stem 4–9 cm in diameter, stem 6–12 cm in diam. with sheath, internodes 4.5–10 cm long; leaf sheath rusty, tubular, 18–28 cm long, brownish, covers with dense irregular spines, all spines flat, straight, black variable in sizes, 0.5–8 cm long; ocrea well developed, spines absent, glabrous; knee conspicuous, glabrous, greenish. Leaves ecirrate, 1.5–2 m long; petiole glabrous, 18–38 cm long, dense grouped spines along the edges, spines variable in sizes, 12–19 mm long; rachis 1.2–1.7 m long; solitary, hooked spines present abaxially on petiole and rachis, spines 4–9 mm long, yellow, arranged in regular interval; leaflets 18–34 on each side of rachis, alternate, equally distributed, linear to ensiform, basal leaflets 42–58 × 2.9–4.1 cm, middle leaflets 58–65 × 2–4.2 cm, apical leaflets 14.2–18.5 × 1.9–2.8 cm, terminal leaflets joined basally. Inflorescences flagelliform, very long; staminate inflorescences 8–9.5 m long, slightly armed with claws, primary bracts cylindrical, obliquely truncate; partial inflorescence 0.4–0.6 m long; bracts cylindrical, open, brown papery after drying, basal bracts tomentose at opening, rachillae opposite, 7–19 cm long. Staminate flowers 4–8 × 3–4 mm. Calyx 3 - lobed; sepals ovate, 3–5 × 1–3 mm, base wide. Stamens 6, dorsifixed, hanging freely; filaments short; anther 2-celled, 2–5 × 1–1.5 mm. Pistillate inflorescence 6–8.5 m long, partial inflorescence 25–55 cm long; primary bracts papery, brownish, 25–55 × 9–16 mm each carrying 15–22 rachillae, individual rachillae 6–15 cm long, with 6–14 pistillate flowers each. Pistillate flowers, 5–7 × 3–4 mm. Calyx cupulate; Sepals 3. Petals 3-lobed, 4–6 × 2–3 mm. Fruits very small, globose, prominently beaked, yellowish, 12–16 × 7–9 mm, covered by triangular scales, inserted in 15 distinct vertical rows; scales 2–4 × 3–6 mm, regular, entire with blackish brown margins. Seeds 6–10 × 4–7 mm, brown with blackish spotted with slightly yellow sarcotesta, on one side flattened with deep germpore, other side convex, endosperm ruminate.

Vernacular name: In Nepalese this species is called “Karalohora, Bethgera”.

Flowering & fruiting: Flowering from January to March and fruiting from April to June.

Habitat: Calamus himalayanus grows along the tropical riverine forest along the lower hilly slopes of Eastern Himalayas between 300–330 m asl. and growing in associated with Achyranthes aspera L., Aglaia spectabilis (Miq.) S.S. Jain & S. Bennet , Dillenia pentagyna Roxb. , Pericampylus glaucus (Lam.) Merr. , Phanera scandens ( L.) Lour. ex Raf., Leea macrophylla Roxb. ex Hornem.

Distribution: Hitherto know from the type locality Mahananda WLS in Darjeeling district of West Bengal.

Etymology: The specific epithet, “ himalayanus ” denotes the type locality which is part of Himalaya a global biodiversity hotspot.

Uses: Leaves and stem are used as thatch and walking stick; local peoples have the fruits to treat diabetes

Notes: The new species is morphologically close to Calamus flagellum Griff. ex Walp. but can clearly distinguished by its smaller sized cluster forming habit, thicker stem diameter with sheath, single type of flat spines on leaf sheath, ocrea surface without spines, conspicuous glabrous knee, much longer 9.5 m flagellate inflorescences, relatively small, globose fruits (12–16 × 7–9 mm), scale rows 15 in number (Table 1). The type locality is situated at lower elevation of riverine forest in the eastern Himalaya of Darjeeling district of West Bengal. The population of the species was found to have a restricted distribution range in the current investigation. This lessknown population of Calamus himalayanus is facing various anthropogenic threats, like mass ecotourism and habitat fragmentation due to road

Table 1. Comparison of diagnostic morphological characters between Calamus himalayanus with its allied species.

network, tea garden extension, and unscientific

withdrawal of plant resources. Therefore, it is

recommended to undertake immediate an in-situ

and ex-situ conservation initiative, even if the

species’ threatened status has not been evaluated.