Casuarinaceae
Shrubs or trees with long or short, slender often weeping branches jointed at nodes. Lvs reduced to many-toothed sheaths surrounding nodes. Fls unisexual; ♂ fls usually in terminal spikes with shortened internodes and bracts fused into a cup, each with 1 stamen, 2 perianth segments and 2 bracts; anther exserted from bracts, 2-locular. ♀ fls in dense, globose to cylindric, sessile or shortly pedunculate heads usually terminal on lateral branches, with each fl. subtended by 2 bracts; ovary superior, 1-locular; style short, the 2 stigmatic branches long-extended; ovules 2-(4), ascending. Fr. in a cone of woody persistent bracts opening at maturity; each fr. a 1-seeded, flattened, indehiscent, terminally winged samara.
Key
4 genera, c. 70 spp., S.E. Asia, S.W. Pacific, chiefly in Australia.
This is a distinctive and unusual family in which both fls and lvs are very reduced to the extent that plants bear a resemblance to gymnosperms. However, the family is now usually considered to be derived rather than primitive. The number of lf-teeth on mature stems is an important diagnostic character. The family was until recently treated as a single genus , Casuarina, but has been divided into 4 genera by Johnson [ see, Johnson, L. A. S., and Wilson, K. L., in Morley, B. and Toelken, H. (Eds) Flowering Plants in Australia (1983)]. All 3 naturalised spp. are also cultivated in N.Z.
