Astronia

Family Melastomataceae. Order Myrtales.

Large trees to shrubs. Buttresses absent. Spines absent. Stilt roots absent. Bark red, gray, brown; not peeling in strips. Vertical stripes in the inner bark or wood absent. Odor absent. 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 opposite; not scale-like; simple; all of the same type; not modified into spines; leathery; gland-dotted, or not gland-dotted; symmetric at the base; not dissected; smooth margined. Epidermis not waxy. Venation trinerved. Secondary veins open; prominent. Smallest veins not prominent, but visible, or not visible; ladder like. Intramarginal vein present. Stalk of blade less than a quarter the length of the blade to a quarter to one half 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, or axillary; on a branched axis; specialized inflorescence units absent; numerous and persistent inflorescence bracts absent. Flowers bisexual; stalked; about 0.5 cm long or across; round; with male or female parts not raised on a column. Hypanthium present. Disk absent. Perianth present; with distinct calyx and corolla whorls. Sepals 5; partially joined; persistent in fruit, or not persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 5; free; not fleshy; deciduous; not stalked; entire. Stamens 10; filaments present; free of each other; free of the perianth; all equal in size; diplostemonous. Anthers 2 loculed; attached along the side; not awned; dehiscing by long slits. Ovary inferior. Carpels joined; 2. Locules 2. Styles solitary. Stigmas 1 lobed; not distinctive. Fruit capsular; non-fleshy; not multiple; splitting; not enclosed in, or sitting on, fleshy perianth parts; wingless. Seeds 100 per fruit (many); barely visible, or less than 5 mm; wingless; uniform in cross-section; aril absent; non-endospermic.

Leaves opposite; palmately veined; intramarginal vein present but no oil glands; petals 5; stamens 10; 2-loculed; berry with numerous small seeds. Taxon images: genastro.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.