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Leaves and fruit. Copyright CSIRO
Cotyledon stage, epigeal germination. Copyright CSIRO
Cotyledon and 1st leaf stage, epigeal germination. Copyright CSIRO
10th leaf stage. Copyright CSIRO
Scale bar 10mm. Copyright CSIRO
Acacia polystachya A.Cunn. ex Benth.
Bentham, G. (1842) The London Journal of Botany 1: 376. Type: Port Bowen, Cunningham, Port Essington, Armstrong; Haggerstons Island, E. Coast (in fruit), Cunningham..
Racosperma polystachyum (Benth.) Pedley, Austrobaileya 2(3): 354(1984), Type: ?.
Dead bark rough and hard to cut.
Leaves green, phyllodineous. Leaf blades about 0.9-17 x 1.6-2.3 cm. A pink or red gland normally visible on the upper side of the leaf blade-petiole junction. Veins longitudinal, anastomosing, usually 2-4 more prominent than the rest, usually running together near the base. Leaf bearing twigs more or less triangular in cross section.
Spikes +/- white, sparse, about 5-8 cm long, on peduncles about 5 mm long. Calyx rather membranous, broad, about 0.7-0.9 mm long, glabrous, lobes fimbriate, about 0.25 mm long. Corolla deeply lobed, glabrous, about 1.5-2 mm long, about 2-2.5 times as long as the calyx. Stamens about 3-4 mm long. Ovary densely pubescent.
Pod +/- flat, usually twisted, curved or coiled to some extent, up to 10 x 0.6-0.8 cm. Seeds black, longitudinally oriented in the pod, about 4.2 x 3 mm. Funicle red or reddish, encircling the seed and thickened to form an aril-like structure beneath the seed.
Cotyledons elliptic, about 4-5 mm long. First leaf pinnate, second leaf bipinnate. By the third or fourth leaf stage: leaves bipinnate, petiole expanded and flattened. At the tenth leaf stage: leaves phyllodineous, linear, glabrous, usually two main veins run from the base to the apex; a gland present on the margin of the leaf blade adjacent to the petiole; stipules very small, visible only with a lens.
Distribution and Ecology
Occurs in CYP and NEQ. Altitudinal range from near sea level to 500 m. Grows in monsoon forest and in drier rain forest but this species probably reaches its best development in gallery forests of Cape York Peninsula. Probably also occurs in New Guinea.