Trichosanthes dunniana H.Lév. subsp. dunniana

Pradheep, K., John, K. Joseph, Singh, P. K., Rathi, R. S. & Pandey, A., 2021, A new subspecies and new records of Trichosanthes (Cucurbitaceae) for India, and notes on T. khasiana, Blumea 65 (3), pp. 233-243 : 237

1. Trichosanthes dunniana H.Lév. subsp. dunniana — Fig. 2a, b ; Map 1

Trichosanthes dunniana H.Lév. (1911) 148; S.K. Chen (1995) 358; Duyfjes & Pruesapan (2004) 85; W.J. de Wilde & Duyfjes (2008) 518; Lu Q.Huang & C.Jeffrey (2011) 42. — Type: J. Esquirol 726 (holo E; iso K), China, Guizhou, Tchen-Fong, 18 July 1905.

Trichosanthes prazeri Kundu (1943) 378. — Type: J.C. Prazer s.n. (holo CAL0000015110 ), Upper Myanmar, Khoni, May 1888.

Medium-sized dioecious climber. Stems sulcate-striate,glabrous; probract subentire, broadly ovate, 2–4 by 3–4 mm, punctate; cystoliths obvious; tendrils 2- or 3-fid. Leaves: petiole 4–5 cm long; lamina ovate-orbicular in outline, 5(–7)-deeply lobed, 8–15 by 7–12 cm, glabrous, membranous, scabrous, base cordate, central lobe elliptic-obovate, narrowed at base, margin coarsely serrate-dentate, apex cuspidate-acuminate, glands 2–5, large, close to the nerve axils towards the blade base, 1–1.5 mm diam. Staminate racemes small, about 10-flowered, glabrescent; bracts persistent, obovate, 20–25 by c. 20 mm, glands few, c. 1 mm diam, margin serrate-laciniate. Staminate and pistillate flowers not seen. Fruits: pedicel 1–2 cm long; ovoid-ellipsoid, 5–9 by 4–7 cm, pericarp 5–10 mm thick, orange-red, pulp greenish black. Seeds brownish, slightly compressed, ovoid-ellipsoid, 10–12 by 5–7 by 3–5 mm, rounded at lateral sides.

Distribution — India (Manipur, Mizoram, Nagaland), China, Myanmar, Thailand and Vietnam.

Habitat & Ecology — Rocky places, forest openings, along roadsides, thickets and stream banks at 600–1700 m altitude. Flowering: July to September; fruiting: October, November.

Note — Jeffrey (1982) synonymised an altogether different species T. majuscula (C.B.Clarke) Kundu (described from Khasi Hills of Meghalaya), under this species, therefore reported its occurrence from India. However, T. majuscula is easily distinguished from T. dunniana by the 3–5-lobed larger leaves (15–20 by 15–20 cm) with lobes measuring not more than 2/3rd depth towards base, ovate-elongate fruits and compressed flat seeds which are belted at the middle. Earlier collections of T. dunniana from India were invariably misidentified as either T. bracteata or T. wallichiana .

Figures

Map 1 Distribution of Trichosanthes dunniana H.Lév. subsp. clarkei K.Pradheep and T. dunniana H.Lév. subsp. dunniana in north-east India.

Fig. 2 Trichosanthes dunniana H.Lév. subsp. dunniana from a. Manipur and b. Mizoram (inset: seed). — c–g.Trichosanthes khasiana Kundu. c. Pistillate flowering twig; d. staminate flowering twig (inset: distal part of staminate flower showing dissected calyx lobes); e. pistillate flower (note the probract); f. longi- tudinal section of pistillate flower exposing style and stigma; g. fruits and seeds. — Photos by K. Pradheep.