Rhododendron

Family Ericaceae. Order Ericales.

Small trees to shrubs. Buttresses absent. Spines absent. Stilt roots absent. Bark gray, brown; not peeling in strips. Exudate absent. Terminal buds not enclosed by leaves.

Complex hairs present, or absent; disk-shaped, or star-like. Stinging hairs absent. Mature twig indumentum absent.

Leaves spiral; not scale-like; simple; all of the same type; not modified into spines; coriaceous, or leathery; not gland-dotted; symmetric at the base; not dissected; smooth margined. Epidermis not waxy. Venation pinnate. Secondary veins open; prominent, or not prominent, but visible. Smallest veins not prominent, but visible, or not visible; net like. Intramarginal vein present, or absent. Stalk of blade absent to less than a quarter the length of the blade; not winged; attached to base of leaf blade; not swollen. Stipules absent. Domatia absent. Basal glands absent. Hairs on mature leaf present, or absent; dense, or sparse.

Inflorescences present, or represented by solitary flowers only; terminal, or axillary; on an unbranched axis, or on a branched axis; specialized inflorescence units present; specialized inflorescence units umbels; numerous and persistent inflorescence bracts absent. Flowers bisexual; stalked; about 0.5 cm long or across, or to about 3 cm long or across, or to about 10 cm long or across; round, or somewhat asymmetric; with male or female parts not raised on a column. Hypanthium absent. Disk present; the stamens outside the disk. Perianth present; with distinct calyx and corolla whorls. Sepals 5(-7); partially joined; persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 5(-7); all joined; not fleshy; deciduous; not stalked; entire. Stamens 5-10(-14); filaments present; free of each other; free of the perianth; all equal in size; isomerous, or diplostemonous. Anthers 2 loculed; attached along the side; not awned; dehiscing by pores. Ovary superior. Carpels joined; 5(-7). Locules 5(-7). Styles solitary. Stigmas 2 lobed; distinctive; head shaped. Fruit capsular; non-fleshy; not multiple; splitting; not enclosed in, or sitting on, fleshy perianth parts; wingless. Seeds 100 per fruit (many); barely visible; wingless; uniform in cross-section; aril absent; endospermic.

Epiphytes to small trees; leaves in pseudowhorls, peltate scales on leaves undersurface (use a lens); flowers in umbel-like inflorescences; calyx, although persistent in fruit, inconspicuous; anthers dehisce through pores; pollen sticky. Taxon images: genrhodo.gif


Cite this publication as: Jarvie, J.K. and Ermayanti (1996 onwards). `Tree Genera of Borneo - Descriptions and Illustrations' URL http://django.harvard.edu/users/jjarvie/Borneo.htm/.
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993) should also be cited.