96 



VASCULAR CRYPTOGAMS 



' vascular ' bundles of the stem are collateral ; the primitive elements of 

 the xylem are usually scalariform tracheides. 



The oophyte generation has been observed in only a few species. In 



Fig. j2.—Oj>hiogloss2aji vnl^atnm L. A, p'ant (natural size) ; B, portion of 



sporophyll (magnified). 



Ophioglossum (pedunculosum, Desv.) it has at first the form of a small 

 round parenchymatous tuber, entirely buried in the soil and destitute 

 of chlorophyll, from which is subsequently developed a cylindrical 

 vermiform shoot, which grows erect by means of a single apical cell, 



