Casuarinaceae

Ramps with verticilated squamiform leaves, male pendulum inflorescences and female capituliforms in a monoica species, Casuarina equisetifolia.

An example of female flowers and pseudo-cons in Allocasuarina distyla.

Seudo-cons mature post opening of bracholas and samaroid fruits Casuarina.

The casuarinaceae (Casuarinaceae) is a family of the order Fagales that includes 4 genera and some 90 accepted species of tropical and subtropical trees and shrubs with very unique morphology within of the Angiosperms.

They are actinorichic plants that fix nitrogen by symbiosis with filamentous bacteria (Frankia).

Features

They are woody, arboreal or shrubby plants, evergreen -referring to the chlorophyllous articles of the twigs, not to the leaves-, monoecious or dioecious (even the same genus can have monoecious and other dioecious species), with young thin grooved twigs, equisetiform, articulated, chlorophyllous, and inconspicuous leaves, marcescent or not, scale-shaped, in whorls that define each article and that, at first sight and for neophytes -and less neophytes-, curiously resemble Gymnosperms. The flowers are very simplified, but their development is very complex; the male ones are arranged in spiciform inflorescences, or the female ones capituliform, in whorls alternating with rows of scale-shaped bracts; the male ones with 4 bracteoles -the internal ones sometimes interpreted as sepals-, and a single bilocular basifix anther stamen and the female ones without perianth, with a reddish bifid pistil and a bicarpelar gynoecium with only one of the carpels -which are fused- fertile. The infructescences are coniform, composed of numerous individual samaroid fruits surrounded by 2 lignified scaly bracteoles, tuberculate or not, very accrescent and that open widely when ripe to release said fruits that contain a single seed each.

Distribution

The family is native to the Old World, the Indo-Malaysian tropics, Australia, and the Pacific islands as far as Colombo and Madagascar. A few of its species are widely naturalized and cultivated as ornamentals throughout the tropical, subtropical, and temperate world..

Common names

The most commonly used common name for Casuarinaceae species is female oak (sheoak or she-oak). Other names include palo hierro (ironwood), roble toro (bull-oak or buloke), and palo res (beefwood).

Taxonomy

The family was described by Robert Brown and published in A Voyage to Terra Australis, vol. 2 P. 571, 1814. The type genus is: Casuarina.