THE CYCAS FAMILY. 



187 



They are either produced solitary, as in the Yew, or 

 few or many in cones, as in Firs, or in globose, or horned 

 galbules, as in the Evergreen Cypress, and Arbor Vitse. 



This class comprises the Cycas, Fir, and Yew families, 

 their special bond of union consisting in their seed 

 ovules being destitute of a coat or covering (thus dif- 

 fering from the usual structure of seeds). They are 

 classed by most botanists under Exogens, and which is 

 the proper place for the two latter families. But having 

 witnessed the germination of many seeds of Oycads, it 

 enables me to say that the embryo has only one coty- 

 ledon, and also that the structure of the stem is endo- 

 genous, as in Palms. Such being the case, gymnogens 

 may be considered to form two natural sub-classes. 

 First, gymnospermous-endogens, the Cycas family ; 

 second, gymnospermous-exogens, the Fir and Yew fa- 

 mily. 



I. Gymnospermous Endogens. 

 The Cycas Family. 



(CyC ADAGES.) 



Stem globose or cylindrical (Palmids), unbranched (rarely 

 forked), their substance composed of three or more concen- 

 tric zones of firm pith, alternating with a narrow zone of 

 woody fibre, the outer consisting of the bases of the fallen 

 leaves, which represent bark, the lateral extension being very 

 limited. Leaves, few or many, terminal ; simply, or rarely 

 twice-winged ; generally very rigid, with or without a mid- 

 rib, and with free veins. Fructification in terminal dioecious 

 cones, formed of fleshy scales. Seed a naked ovule, being a 

 waxy or horny albuminous nut, the embryo germinating with 

 one cotyledon (fig. 13, a). 



This remarkable family of plants consists of about 50 

 species, all being widely distributed within or near the 



