Shrubs, trees, or lianas, rarely undershrubs or herbs, with a very strongly developed and layered, fibrous, tough bast (“Seidenbast”, silky fibres). Leaves opposite or decussate, spiral or alternate, very rarely some ternate, simple, entire, exstipulate, articulated at the base, glandular-punctate in Gonystyloideae. Inflorescences terminal, axillary or extra-axillary, or on internodes, sometimes on brachyblasts, simple or rarely branched, sessile or peduncled, racemose, umbelliform, spicate, capitate, or fascicled, obviously basically racemose; flowers rarely solitary, sometimes cauliflorous and condensed into glomerules, bracteate (bracts sometimes forming an involucre) or ebracteate. Flowers bisexual (rarely unisexual by abortion and polygamodioecious or dioecious in extra-Mal. spp.), homomorphic, rarely heteromorphic, regular, tubular, campanulate or infundibuliform, tube very short in Gonystyloideae, or with almost free sepals in extra-Mal. spp., mostly caducous, some circumsciss in the lower part, or persistent (sometimes enveloping the ripe fruit in extra-Mal. spp.), sometimes slit lengthwise in fruit, 4-5(-6)-lobed, the lobes imbricate (rarely valvate in some extra-Mal. spp.), equal or rarely the interior 2 slightly smaller, erect or reflexed. Corolla absent or represented by free or united petaloid appendages, isomerous and alternating with the calyx lobes, or double in number and arranged in pairs opposite the calyx lobes, rarely more (Gonystylus), fleshy or membranous, filamentous or oblong, entire or lobed, rarely united into a ring, inserted at the throat of floral tube or slightly lower, sometimes behind the stamens, or absent. Stamens 2 only, or 4-~, in Malaysia (except in some Gonystyloideae) mostly diplostemonous, in two or in one series, if in two series then at two different levels, the upper ones opposite the calyx lobes and the lower ones alternate with them, sessile or filamentous; filaments filiform or slightly flattened, entirely or partly adnate to the floral tube; anthers 2-celled, basi- or dorsifixed, obtuse or apiculate, introrse, hippocrepiform (Gonystyloideae), or extrorse (extra-Mal. spp.), dehiscing length-Wise, usually free, sometimes the lower 1/3—1/2 adnate to the tube (Aquilaria cumingiana) Disk hypogynous, membranous or subcarnose, annular, cupular, obed, free and scale-like, or none. Ovary superior, 1-2-celled, 3-5(-8)-celled in Gonystyloideae and extra-Mal. spp., sessile or shortly stalked; style filiform, caducous, sometimes very short or obscure, terminal or excentric, in Gonystyloideae sometimes accompanied by ‘parastyles’ at the base; stigma capitate, subglobose, oblong, subclavate or pyramidal, entire and smooth, or slightly emarginate, sometimes papillose. Ovules solitary in each cell, with axial or parietal placentation, pendulous from near the top, sometimes partly or entirely and laterally adnate to the placenta, the micropyle towards the top and outward. Fruit a drupe or drupaceous, a berry, or a capsule, either apically or laterally emerging from the floral tube, 1- or 2(-3)-seeded, or 3-5(-8)-seeded in Gonystyloideae and extra-Mal. spp.; pericarp membranous, pulpy, coriaceous, or fibrous. Seeds with a caruncle-like or tail-like appendage, usually with an aril in Gonystyloideae, the seed usually hanging out by one end on a thin, string-like funicle in Aquilarioideae; testa usually crustaceous, black, often with rather irregular ridges, glabrous or short-hairy in some spp. of Aquilarioideae; albuminous or exalbuminous. Embryo straight; cotyledons plano-convex; radicle short, superior. Distribution. About 50 genera with about 500 species, chiefly developed in south and tropical Africa and Australia; it is almost cosmopolitan.