Pleiospermium

Family Rutaceae. Order Rutales.

Large trees to shrubs. Buttresses absent. Spines present; on trunk, or on branches. Stilt roots absent. Bark 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 absent. Stinging hairs absent. Mature twig indumentum absent.

Leaves spiral; not scale-like; simple, or compound (rarely); with three leaflets; with a terminal leaflet; leaflets opposite; of different sorts on a single twig, or all of the same type (simple and occasional compound); not modified into spines; coriaceous, or leathery; gland-dotted; symmetric at the base; not dissected; smooth margined. Epidermis not waxy. Venation pinnate. Secondary veins open; prominent. Smallest veins prominent; net like. Intramarginal vein present. Stalk of blade less than a quarter the length of the blade; winged (widely by the blade, tapering to the base), or not winged; attached to base of leaf blade; swollen; swollen at one end. Stipules absent. Domatia absent. Basal glands absent. Hairs on mature leaf absent.

Inflorescences present; terminal (pseudo), or axillary; the flowers from a single point on the stem, or on an unbranched axis, or 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 raised on a column, or not raised on a column; with the female parts of the flower raised on a stalk. Hypanthium absent. Disk present; the stamens outside the disk. Perianth present; with distinct calyx and corolla whorls. Sepals 4-5; partially joined; persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 4-5; free; not fleshy; deciduous; not stalked; entire. Stamens 8, or 10; filaments present; free of each other; free of the perianth; of different sizes (alternating short and long); diplostemonous. Anthers 2 loculed; attached along the side; not awned; dehiscing by long slits. Ovary superior. Carpels joined; 4-5. Locules 4-5. Styles solitary. Stigmas 1 lobed; distinctive; head shaped. Fruit berry-like; fleshy; not multiple; not splitting; not enclosed in, or sitting on, fleshy perianth parts; wingless. Seeds 2-10 per fruit; less than 5 mm; wingless; uniform in cross-section; aril absent; endospermic.

Petioles strongly winged, wide at the top and tapering to the base; spines numerous on trunk and branches. Taxon images: pleiosp.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.