100 CASUARINACEAE. 



. Sepals valvate ; placentae united in the axis. Order 16. Malvales. 

 Sepals or calyx-segments imbricated or con- 

 volute ; placentae mainly parietal, 

 sometimes united in the axis. 

 Sepals separate. Order 17. Hypericales. 



Sepals united. Order 18. Passiflorales. 



B. Ovarii inferior, adnate to the calyx, wholly or in part (except in Lythraceae 

 where it is usually merely enclosed by it). 

 Herbs with barbed or stinging hairs. Order 19. Loasales. 



Plants without barbed or stinging hairs. 



Fleshy spiny plants, with jointed stems, the 

 leaves mostly very small or none ; calyx-seg- 

 ments and petals several or numerous. Order 20. Opuntiai.es. 

 Herbs, shrubs or trees, not fleshy or spiny ; 

 calyx-segments rarely more than 5. 

 Ovules several or numerous in each cavity 

 of the ovary (except in Haloragidaceae, 



aquatic herbs). Order 21. Myrtales. 



Ovule 1 in each cavity of the ovary. Order 22. Ammiales. 



Order 1. CASUARINALES. 



Trees or shrubs, with very slender, jointed, angled branches and twigs, 

 the leaves reduced to minute verticillate scales at the nodes, the scales 

 sometimes connate, the small imperfect bracted flowers in terminal spikes 

 or cone-like heads. Staminate flowers with 1 or 2 sepals and 1 stamen 

 with a large anther. Pistillate flowers without a perianth; ovary small, 

 1-celled; style short, with 2 slender branches; ovules 1 or 2, ascending. 

 Fruit a cone-like mass of accrescent bracts, subtending winged achenes. 

 Seed with a membranous testa and no endosperm, the embryo straight. 



Family 1. CASUARINACEAE Lindl. 

 Beef-wood Family. 

 Only one genus, with about 25 species, most abundant in Australasia. 



1. CASUARINA Forst. Char. Gen. PI. 104. 1776. 



Characters of the order. [From the zoological name of the Cassowary.] 

 The following species is typical. 



^ 1. Casuarina equisetifolia Forst, Char. Gen. PI. 104. 1776. 



A tree, reaching in the American tropics a maximum height of about 20 m. s 

 with a trunk up to 1 m. in diameter, much larger in Australia, with long and 

 slender branches, the upper ones erect or nearly so, the dark brown bark fur- 

 rowed. Twigs angular, very slender, drooping; leaves 6-8 in each whorl, only 

 1-3 mm. long, acute, appressed, ciliate, decurrent on the twigs; staminate 

 flowers in slender terminal cylindric spikes 1-4 cm. long, the bracts imbricated, 

 the anthers exserted; pistillate flowers in lateral dense subglobose heads which 

 become about 2 em. in diameter in fruit. 



Sandy sea shores, spontaneous after cultivation, Abaco, Andros, New Provi- 

 dence, Eleuthera, Crooked Island, the Caicos, Grand Turk, and Inagua : A native 

 of Australia more or less naturalized in Florida, the West Indies and Yucatan. 

 Erroneously called Spanish Cedar. Beef-wood. 



