SECT. II 



PHANEROGAMIA 



437 



cotyledons. The prothallium, sometimes called the ENDOSPERM, 

 envelops the embryo, and serving during germination as a nutritive 

 tissue, contains a large amount of reserve material, such as albuminous 

 substances, starch, and fat. The periphery of the seed is occupied by 

 a hard or, in its outer portions, succulent sheath, which in some cases 

 is surrounded by a cupular fleshy aril. 



The fruit resembles the female flower, but it is much larger. The 

 oarpellary scales become woody after fertilisation, rarely fleshy and 

 juicy. 



The Gymnosperms are all woody plants, with secondary growth in 

 thickness. Their leaves are either simple, and then for the most part 

 needle or scale-like, or they may be pinnate. 



Order 1. Cyeadinae 



This order includes the single family Cycadaeeae. — Flowers 

 dioecious, WITHOUT A PERIANTH, consisting of many spirally-arranged 

 leaves ; staminal leaves with many pollen-sacs ; carpellary leaves usually 

 with two ovules. For the 

 most part, UNBRANCHED, 

 evergreen woody plants, 

 devoid of true vessels and 

 having MUCILAGE DUCTS in 

 all organs. Leaves LARGE 



AND PINNATE (Fig. 369). 



Many Cycadaeeae re- 

 semble the Tree-Ferns not 

 only in their column-like, 

 unbranched stem and apical 

 rosette of large, pinnate 

 leaves, but also in their 

 dimensions, attaining some- 

 times a height- of 12 m.; 

 in other cases the stems 

 are shorter, resembling 

 the Marattiaceae more in 

 habit; they are tuberous 

 and partially buried in the 

 ground. The branching 

 is limited to the flowering 

 region, although sometimes adventitious shoots spring from the stem. 

 In most species {e.g. Cycas) the stem is invested with a thick armour 

 of woody scales, which are in part the basal portions of dead and 

 fallen foliage-leaves, and in part scale-leaves (cataphylls), the develop- 

 ment of which alternates periodically with that of the foliage-leaves. 



The flowers of the Cycadaeeae are always terminal ; the stem, 



Fig. 369. — Cycas revoluta. 1, Female tree ; 2, carpellary leaf 

 with ovules ; 3, staminal leaf ; 4, seed. (After Wossidlo.) 



