Scientific name: Macrosolen bidoupensis Tagane & V.S.DangEnglish name: Vietnamese name: Đại cán bidoupOther name:
Macrosolen bidoupensis is similar to Macrosolen tricolor Danser of China, Laos and Vietnam in leaf shape and size and by possession of a 2-flowered umbel, but differs in having a sessile to very short petiole (up to 0.7 mm long in M. bidoupensis vs. 2–3 mm long in M. tricolor), more lateral veins (4 or 5 vs. 2 or 3 pairs), slightly cordate to rounded leaf bases (vs. cuneate) and a basally green corolla tube (vs. reddish around the basal 1/3). The leaf shape is also somewhat similar to Macrosolen platyphyllus Danser of Thailand, Peninsular Malaysia and Borneo, but easily distinguished in having much smaller leaves and flowers, and very short petioles.
Hemi-parasitic shrub, 25–40 cm tall, totally glabrous. Branches terete, grayish to grayish brown, lenticellate. Leaves opposite; blade elliptic, broadly elliptic, broadly ovate-elliptic, or circular, 1.2–4.8 × 1.2–3.5 cm, coriaceous, apex broadly obtuse to rounded, base slightly cordate to rounded, margin entire, grayish green and slightly lustrous adaxially, dull olive abaxially, midrib prominent at basal 1/3 to 1/2 abaxially, secondary veins 4 or 5 pairs, obscure or visible adaxially, obscure to faintly visible abaxially; petiole to 0.7 mm long. Inflorescences axillary, sometimes at older leafless nodes, 2-flowered umbels; peduncle ca. 0.9 mm long. Pedicel 1.1–1.5 mm long; central bract suborbicular, ca. 1 mm long, bracteoles suborbicular, connate, ca. 1 mm long; mature buds 2.8–3.2 cm long; calyx limb (calyculus) annular, ca. 0.7 mm long; corolla green tinged with red at top of tube and lobes, symmetrically 6-winged at about two thirds the length, tube 2.2–2.4 cm long in anthesis, gradually dilated, inflated, slightly curved, lobes lanceolate, 6–8 mm long, reflexed in anthesis; stamens 6, anthers ca. 2.3 mm long, filaments basally adnate to corolla tube, free part 2.3–3.3 mm long; ovary 2.8–3.3 mm long; style 2.8–3.2 cm long, stigma capitate. Berry reddish orange, subglobose to slightly depressed-barrel-shaped, ca. 8 mm high, ca. 6 mm wide, ovoid when dry, apex beaked by calyx limb. Seed 1, ellipsoidal, ca. 5 mm high, ca. 3 mm wide, longitudinally 6-grooved. The measurements of the flower characters are derived from the spirit collection.
Flowering and fruiting specimens were collected in February.
Distribution and habitat
Vietnam (so far known only from Bidoup Nui Ba National Park, Lam Dong Province). In lower montane evergreen forest, ca. 1500 m altitude.