Subclass Monocotyledones 



HIS subclass of plants is characterized by the simplicity of its stem 

 structure, the fibro- vascular bimdles being arranged in a single column 

 without pith or medullary rays, consequently there are neither radiat- 

 ing nor concentric markings in the wood. The outer portion is with- 

 out true bark, being of the same structure as the inner, except that it is more 

 compact and harder, the woody bimdles being closer together with less cellular 

 tissue intervening. The stems are usually not enlarged by growth near the cir- 

 cumference, as there is no cambium; on this account they are also called Endogens 

 or inside growers. 



The leaves, with few exceptions, are parallel- veined, there being few connect- 

 ing or reticulating ve;ins; the leaves are also usually alternate and without stipules, 

 and, with the exception of the palms, are mostly simple. 



The seed, however, affords the most striking characteristic of this subclass, in 

 that its embryo has but one cotyledon (seed-leaf), hence the name Monocotyle- 

 dones. 



Most of the plants of this subclass are herbaceous; the greater number of aqua- 

 tic flowering plants belong here, also the Grasses, Sedges, Lilies, Bananas, and 

 Yams; the woody plants of this group are mostly members of the Smilax family, 

 climbers often called Greenbriers, the roots of some species constituting the well- 

 known drug called Sarsaparilla; of the Dracaena family, and the Palms, the two 

 latter groups being represented in our fliora by some 20 arborescent species. 



Leaves pinnately or palmately compound; ovule i in each cavity of the ovary. 



« Palm Family. 



Leaves simple, elongated; ovules many in each cavity of the ovary. 



Dracaena Family. 



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