Drypetes kalamii G. Krishna, Karthig., Arisdason et Chakrab., 2017

Krishna, Gopal, Karthigeyan, K., Arisdason, W. & Chakrabarty, T., 2017, A new species of Drypetes (Putranjivaceae / Euphorbiaceae s. l.) from West Bengal, India, Phytotaxa 319 (3), pp. 271-276 : 271-275

Drypetes kalamii G. Krishna, Karthig., Arisdason et Chakrab. , sp. nov. Figs. 1 , 2

Diagnosis: —The new species most closely resembles Drypetes ellisii S.P. Mathew & Chakrab. (1990: 639) but differs in being small shrub (female plants) or scrambling shrub (male plants) with corrugated branches and puberulous branchlets, longer petioles, laminae abruptly acuminate with pointed apices, fruiting pedicels slender and puberulent with bracts and bracteoles and smaller, ovoid-globose drupes in fascicles of 3–5.

Type: — INDIA. West Bengal: Jalpaiguri district, Chilapatha, near Nalraja Ghar , 26°34’07.5” N, 089°22’43.5” E, 27 September 2012, K. Karthigeyan 59100 (holotype, CAL!; isotype, ASSAM!) .

Dioecious, small shrubs, erect, to 1 m high (female plant) or scrambling shrubs (male plant); bark greenish; branches spreading, terete, 1–4 mm in diam., corrugated, minutely scattered tawny-pubescent. Leaves alternate, stipulate; stipules deltoid, c. 0.5 mm, puberulent; petioles 1–1.8 cm long, semiterete, 1–1.5 mm in diam., geniculate, pulvinate at apex, puberulent; laminae oblong to oblong-elliptic, 8.5–25 × 3.5–8.5 cm, base oblique and acute or sometimes rounded, margins entire, sometimes undulate, apex abruptly acuminate with pointed acumen (5–20 mm long), thin-coriaceous, glabrous, greenish brown when dry; midrib flattened above and raised beneath; lateral veins 6– 10 pairs, faint above and prominent beneath, forming loops near margins, veinlets inconspicuous above and prominent and finely reticulate beneath. Inflorescences fascicles, usually in the axils of fallen leaves; the staminate 7–50-flowered; the pistillate flowers not seen. Male flowers: c. 10 mm long, greenish when immature, turning pale yellow at maturity; pedicels filiform, c. 5 mm long, densely strigose; bracts ovate, c. 0.5 mm, slightly concave, margins strigose-ciliate, densely strigose outside, glabrous inside; bracteoles smaller than bracts, ovate, surfaces similar to bracts. Sepals 4(or 5), unequal, strongly imbricate, broadly ovate-orbicular, 1.5–2 × 1–1.5 mm, concave, apex obtuse, glabrous; stamens 10(–12); filaments distinct, c. 0.5 mm long, thickened, glabrous; anthers c. 0.4 × 0.3 mm, glabrous; disk folded, lobed, glabrous; pistillode absent. Female flowers not seen. Drupes 3–5 per fascicle, ovoid-globose, 8–10 mm in diam., 1- locular, glabrous, green, turning orange-red to red when ripe; bracts and bracteoles deltoid, c. 0.25 mm, puberulent; pedicels 5–6 mm long, sparsely puberulent. Seed 1, subglobose, smooth.

Flowering: —March–April(–May?); Fruiting: —June–September.

Habitat: —Wet shaded localities in subtropical moist semievergreen forests, at 50–100 m elevation; usually in association with Psychotria calocarpa Kurz , Ixora longibracteata Bremekamp , Cleidion javanicum Blume and Elatostemma repens (Loureiro) Hallier f.

Distribution: —Known only from Buxa National Park and Jaldapara National Park in West Bengal, India. (Map).

Paratypes: — INDIA. West Bengal: Alipurduar district, Buxa National Park, Jainty Forest Range, 26°37’55.86” N, 089°35’05.82” E, 5 March 2011, Gopal Krishna 47273 ( CAL!, ARUN!) ; Rajabhatkhawa Forest Range, 26°39’11.99” N, 089°37’25.50” E, 5 April 2012, Gopal Krishna 56037 ( CAL!) ; Jalpaiguri district, Chilapatha , 26°35’13.5” N, 089°22’18.3” E, 2 March 2013, K. Karthigeyan 59226 ( CAL!) ; Chilapatha , 26°38’45.7” N, 089°21’54.5” E, 5 June 2013, K. Karthigeyan 59370 ( CAL!) .

Etymology: —The specific epithet honours Dr. Avul Pakir Jainulabdeen Abdul Kalam (Dr. A.P.J. Abdul Kalam), the 11th President of Republic of India, professor and aerospace scientist, for being an inspiration to the entire scientific community, especially the students and young researchers.

Conservation Status: —During the study male plants (30–40 individuals) were recorded from two localities (Jayanti and Rajabhatkhawa Forest Ranges) in the Buxa National Park, and a few male and around 20 female plants are located in one locality (Chilapatha Forest Range) in Jaldapara National Park. It is provisionally assessed here as “Critically Endangered” following the IUCN Red List Categories and Criteria version 3.1 (2012). Grazing and forest fires are two plausible threats to this species.

Note: —This new species is unique among the Indian Drypetes in having small shrubby/scrambling life-form and having prominent bracts and bracteoles. This species also resembles D. porteri Pax & Hoffmann (1922: 268) , but the latter differs primarily in its arborescent habit, much smaller leaves, shorter petioles that are neither geniculate nor pulvinate, and male flowers with 24 stamens and sepals without being inwardly curved. The characters that distinguish the new species from its closely similar species are provided in Table 1.

MAP. Distribution of Drypetes kalamii G. Krishna, Karthig., Arisdason et Chakrab.

Figures

FIGURE 1. Drypetes kalamii G. Krishna, Karthig., Arisdason et Chakrab.: a. Flowering-twig (male); b. Fruiting-twig; c. Male flower; d. Sepals with stamens; e. Sepal (male flower); f. Disk with bracteoles; g, h. Bract (abaxial and adaxial sides); i. Stamen [illustration drawn from Gopal Krishna 47273 (male plant) and K. Karthigeyan 59100 (female plant) by D.K. Sah].

FIGURE 2. Drypeteskalamii G. Krishna, Karthig.,Arisdason et Chakrab.:a, b. Habit:a. Male plant; b. Female plant; c. Male inflorescence; d. Fruits (photos: a, c. G. Krishna; b, d. K. Karthigeyan).