Polyosma

Family Grossulariaceae. Order Rosales.

Large trees to shrubs. Buttresses absent. Spines absent. Stilt roots absent. Bark red, gray, brown; not peeling in strips. Slash yellow, red, brown. Vertical stripes in the inner bark or wood absent. Odor absent. Exudate absent. Terminal buds not enclosed by leaves.

Complex hairs absent. Stinging hairs absent. Mature twig indumentum present, or absent; dense, or sparse.

Leaves opposite; not scale-like; simple; all of the same type; not modified into spines; coriaceous, or paper-like; gland-dotted, or not gland-dotted; symmetric at the base; not dissected; smooth margined, or with small to large teeth on margin. 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. Stalk of blade 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; terminal; on an unbranched axis; specialized inflorescence units absent; numerous and persistent inflorescence bracts absent. Flowers bisexual; stalked; about 0.5 cm long or across, or to about 3 cm long or across; round; with male or female parts not raised on a column. Hypanthium present. Disk present; the stamens outside the disk. Perianth present; with distinct calyx and corolla whorls. Sepals 4; partially joined; persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 4; free; not fleshy; deciduous; not stalked; entire. Stamens 4; filaments present; free of each other; free of the perianth; all equal in size; isomerous; opposite the sepals (when isomerous). Anthers 2-4 loculed (2 or 4); attached by the base; not awned; dehiscing by long slits. Ovary partly inferior, or inferior. Carpels joined; 2. Locules 1. Styles solitary. Stigmas 1 lobed; not distinctive. Fruit berry-like; fleshy; not multiple; not splitting; not enclosed in, or sitting on, fleshy perianth parts; wingless. Seeds 1 per fruit; less than 5 mm, or about 1 cm long; wingless; uniform in cross-section; aril absent; endospermic, or non-endospermic.

Leaves opposite and with inset intramarginal vein; flowers with 3 bracteoles; hypanthium present; petals hairy outside, long hairy inside. Taxon images: polyosma.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.