Hopea sasidharanii Robi & Sujanapal, 2020

Robi, Aloor Jose, Sujanapal, Puthiyapurayil, Sreekumar, Vadakkethil Balakrishnan, Sanil, Madambi Sankarankutty & Dantas, Kuttikkattu Jose, 2020, Hopea sasidharanii (Dipterocarpaceae) - a new species from southern Western Ghats, India, Phytotaxa 429 (2), pp. 167-172 : 167-171

Hopea sasidharanii Robi & Sujanapal sp. nov. ( Figs. 1 , 2 & 3 )

Morphologically similar to Hopea utilis , but differs by the elliptic or elliptic-ovate (vs. linear-lanceolate), thickly coriaceous leaves (vs. thinly coriaceous) entire margin (vs. slightly undulate); lateral veins 5–9 (vs. 10–12), looped near the margins (vs. not looped), the two basal nerves opposite (vs. basal pairs alternate); sparsely puberulent inflorescence (vs. densely grey pubescent); purplish flower buds (vs. white); hour-glass shaped ovary (vs. ovoid) with prominent stylopodium and the ovoid (vs. globose) fruits. ( Table 1).

Type:— INDIA. Kerala: Kollam district, Shenduruny Wildlife Sanctuary , Choondippara , ± 500m a.s.l., 19 March 1993, N. Sasidharan 10303 (Holotype KFRI!; Isotypes KFRI!, MH!)

Evergreen tree, 15–20 m tall. Bark thick, pale brown, inner bark creamy or pale yellow; branchlets subterete, glabrous. Leaves simple, alternate, distichous, petiolate; petiole 9–14 mm long, thick, glabrous; lamina elliptic, elliptic-ovate, 7.5–21.5 × 3.5–8 cm, sub-rounded, obtuse or cuneate at base, margin entire, acute at apex, thickly coriaceous; lateral nerves 5–9 pairs, basal 2–pairs opposite, pinnate, prominent, secondary veins arcuate, narrowly depressed above, raised below; tertiary veins reticulate to scalariform-reticulate, faint above, prominent below, domatia absent. Inflorescence axillary to ramiflorous; panicles 7–13.5 cm long, lax, erect, sparsely puberulent; branches 5–9, alternate, ca. 3 cm long, slightly curved, bearing 4–8 secund flowers per branch; bracteole fugacious. Flower buds ovoid, purplish, pedicellate; pedicels ca. 3 mm long, stout, pubescent. Flowers 5–merous, actinomorphic, bisexual. Sepals 5, broadly ovate, subequal, 3–4 × 1.5–2 mm, minutely connate at base, hirsute, ciliolate along margin, obtuse at apex. Petals 5, pale yellow, twisted, falcate-oblong, ca. 8.5 × ca. 3 mm, partly hirsute dorsally, glabrous inside, connate at base, entire or ciliate, obtuse or undulate at apex, membranous, veins 7–10. Stamens 15 in 2 whorls, adnate to corolla base, ca. 2 mm long; filaments ca. 1 mm long, compressed at base, tapering, glabrous; anthers suborbicular, ca. 0.3 mm long, dehiscence longitudinal; connective-appendages flagellate at apex, filiform, ca. 0.5 mm long. Ovary ovoid, ca. 1 mm long, hirsute; ovary and stylopodium hour-glass shaped, tapering into style; style thick, ca. 0.6 mm long, glabrous. Fruits ovoid, 1.5 × 0.7 cm, obtuse at apex, enclosed by the persistent, subequal, thick sepals, fruit pedicel absent.

Distribution:—Endemic to southern Western Ghats, India. So far, known only from the type locality. About 10 individuals were located in two populations at the type locality.

Ecology:—Rare in evergreen forests, along the foot hills and associated with Ellipanthus neglectus Gamble (1917: 26) , Hydnocarpus macrocarpa (Bedd. 1873: 236) Warb. (1893: 21) , Acrotrema arnottianum Wight (1840: 9) .

Phenology:—Flowering: March–May; Fruiting: May–August

Etymology:—The specific epithet of the new taxon is in honor of Dr N. Sasidharan, Deputy Regional Director, National Medicinal Plants Board, Southern region, Kerala Forest Research Institute, Peechi for his valuable contributions to the field of angiosperm taxonomy and floristics.

Additional specimens examined (Paratype):— INDIA. Kerala: Kollam district, Sangili river, Shenduruny Wildlife Sanctuary, ± 400m a.s.l., 11 May 2015, A. J. Robi 23903 ( KFRI!)

Figures

FIGURE 1. Hopea sasidharanii Robi & Sujanapal sp. nov.: A. Habit; B. Inflorescence with flower & buds; C. Flower enlarged; D. Sepal; E. Petal; F. Stamen; G. Pistil; H. Fruit.

FIGURE 2. Hopea sasidharanii Robi & Sujanapal sp. nov.: A. Habit; B. Mature trunk with bark; C. Trunk with inner bark; D. Twig showing adaxial view of leaves; E. Twig showing abaxial view; F. Leaf base & basal opposite nerves.

FIGURE 3. Hopea sasidharanii Robi & Sujanapal sp. nov.: A. Flowers-top view; B. Inflorescence; C. Sepals; D. Petals; E. Stamens; F. Pistil; F. Fruits.