Description: Small tree, 10–15 m tall, bark smooth, blackish, bark inside with tough silky fibres. Leaves alternate, exstipulate; blade oblong to lanceolate, chartaceous, shining, almost glabrous on both surfaces, 4–7.5 x 1.5–3.5; margin entire, revolute; apex caudate, 1–2 cm long; base cuneate; secondary nerves, many, subparallel, arching to margin forming as intramarginal vein, evident on both surfaces; tertiary nerves fine subparallel; midrib sunk above, prominent below; petiole ca 0.5 cm. Inflorescences 2–3 flowers in fasicles, pseudoterminal or axillary, pubescent; pedicels ca 0.5 cm. Calyx tubular, pubescent, creamy, ca 1 cm long; lobes 5, imbricate, persistent, 1.5–2 mm long. Petals (petaloid appendage) 5, scale like, inserted on calyx tube between calyx lobes, densely pubescent, ca 0.5 mm. Stamens 5, inserted to the calyx tube opposite calyx lobes, sessile; anthers lanceolate ca 1.5 mm long. Ovary superior, 2 locular, oblong, pubescent; ovule 1 in each locule; style simple; stigma globose. Fruits capsule, up to 3 cm long; peduncles to 2 cm long (after HÔ, 1992).
Taxonomy Phylogenetic analysis using the plastid trnL-trnF polymorphisms indicated that species of Aquilaria and Gyrinops are intermixed in one monophyletic group (Eurlings & Gravendeel, 2002. There are several suggestions (Hallier f., 1922; Ding Hou, 1960) that both genera should be merged and that the single morphological character separating them (a different number of stamens (10 in Aquilaria) does not reflect evolutionary relationships. However, Ding Hou (1960) retained the two genera in his Flora Malesiana. The genus Gyrinops is found from Sri Lanka, eastern Indonesian islands (Lombok, Sumbawa, Flores, Sumba, Sulawesi and the Moluccas) and in New Guinea. It consists of nine species, one in Thailand. |
