Casuarina, also known as she-oak, Australian pine and native pine, is a genus of flowering plants in the family Casuarinaceae, and is native to Australia, the Indian subcontinent, Southeast Asia, islands of the western Pacific Ocean, and eastern Africa.
Plants in the genus Casuarina are monoecious or dioecious trees with green, pendulous, photosynthetic branchlets, the leaves reduced to small scales arranged in whorls around the branchlets, the male and female flowers arranged in separate spikes, the fruit a cone containing grey or yellowish-brown winged seeds.
Description
Plants in the genus Casuarina are dioecious trees (apart from C. equisetifolia that is monoecious), with fissured or scaly greyish-brown to black bark. They have soft, pendulous, green, photosynthetic branchlets, the leaves reduced to scale-like leaves arranged in whorls of 5 to 20 around the branchlets. The branchlets are segmented at each whorl with deep furrows that conceal the stomates. Male flowers are arranged along branchlets in spikes with persistent bracteoles, female flowers in spikes on short side-branches (effectively "peduncles") that differ in appearance from vegetative branchlets. After fertilisation, the female spikes develop into "cones" with thin, woody bracteoles that extend well beyond the cone body. The cones enclose grey or yellowish-brown winged seed known as samaras.
Ecology
Casuarina are attacked by a range of herbivorous insects.
Hymenoptera: The wasps Bootanelleus orientalis and another Bootanelleus species (Torymidae) feed on seeds. Selitrichodes casuarinae and S. utilis (Eulophidae) induce galls.
Lepidoptera: Most lepidopteran herbivores are in the family Oecophoridae. Zauclophora pelodes, Araeostoma aenicta and Lichenaula sp. feed on leaves, and the latter two are also leaf tiers. Cryptophasa irrorata bores in branches and stems. Outside of Oecophoridae, there are fruit- and leaf-feeders in families Carposinidae and Gelechiidae.
Curculionidae: A weevil in genus Haplonyx...
