CCXXIV. CYCADE^. 753 



ridge {Gycas), or pinnate from a midrib, and then simple or bifurcate (Stangeria). 

 Vernation various : (1) petiole and leaflets rolled into a crozier, as in Terns ; (2) 

 petiole alone involute, and leaflets imbricate ; (3) petiole straight, and leaflets folded 

 along their midrib and juxtaposed. Flowees achlamydeous, dioecious, collected into 

 strobiH or terminal cones ; $ forming large ovoid or oblong cones ; scales thickly 

 coriaceous, oblong, or dilated at the apex, which is plane (Zamia), or cuspidate 

 {Oycas), or bidentate {Geratommia), bearing on their dorsal face numerous 1-celled 

 coriaceous anthers, which cover the face of the scale {Gycas), or form two groups along 

 the midrib {Zamia), dehiscence longitudinal ; pollen hyaline, globose or ellipsoid. — 

 Flowees 2 : Ovaet, style, and stigma ; scales foUiform, imbricate, forming a sort 

 of cone at the top of the stem, crenellated and bearing in each crenature an erect 

 ovule [Gycas) ; or forming a true peduncled cone {Zamia), composed of stipitate 

 peltate scales, under which are placed, 2 ovules ; ovules naked, sessile, orthotropous. 

 Seed drupe-like, presenting several openings corresponding to the embryonic 

 vesicles, from which descend folded cords, terminated by embryos of which one only 

 is developed ; testa fleshy without, crustaceous within ; albumen fleshy, thick, in the 

 centre of which is the cavity containing the perfect embryo. Embeto appearing 

 undivided, owing to the cohesion of the cotyledons ; radicle superior {Gycas), or 

 inferior, or obliquely directed towards the rachis {Zamia, &c.); cotyledons unequal, 

 often hypogeous in germination, 



PRINCIPAL GENERA. 



* Cycas. * Macrozamia. * Dioon. Bowenia. * Zamia. 



* Oeratozamia. * Stangeria. Encephalartos. Microcycas. 



CycadecB, whicli the earlier botanists, relying on habit and vernation, placed near either the Palms 

 or Tree-ferns, and other Cryptogamic families, are evidently Dicotyledons, and closely allied to Conifm-ce ; 

 the anatomy of the stem, inflorescence, structure of the stamens, ovules, seeds and embryo, are almost 

 identical in the two families ; besides vyhich, in Vycadece the ovules are sometimes geminate, with an 

 inferior micropyle as in Abietinece; or solitary with a superior mioropyle,"as in Taxinece (Salisburya). 

 The only important difference is in the habit and foliation of Cycadem. Cycas more frequently inhabits 

 tropical Asia and its large islands, but .also Madagascar and equatorial Australia. Macrozamia [and 

 Boioenid] is peculiar to Australia. Enoephalartos and Stangeria are South African. 2kimia, Microcycas, 

 Cei-atozamia, and Dioon are tropical and sub-tropical American. 



The central and cortical pith of Cycadets abounds in nutritious starch. The Cycas of the Moluccas 

 and of Japan yields a sort of sago, with which the natives make bread. The Hottentots feed on the 

 [pith of the] Encephalartos, called by the Dutch colonists Broodboom (Bread-tree). The seeds of Cycas 

 and Zamia are edible, containing starch combined with a gummy matter, but they are astringent in the 

 raw state ; those of an Australian species are reputed to be violently emetic. 



