XXIV KEY TO THE ORDERS. 



III. GLLTMACEOUS DIVISION. 



Flowers without a true perianth, but subtended by thin 

 scales called glumes. 



CYPERACE^E. Sheaths of the leaves not split 248 



GRAMINE^E. Sheaths of the leaves split on the side away 



from the blade 251 



SERIES II. CRYPTOGAMS. 



Plants without stamens and pistils, reproducing themselves 

 by spores instead of seeds. 



CLASS III. PTER1DOPHYTES. 

 Stem containing vascular as well as cellular tissue. 



FILICES. Spores produced on the fronds 257 



EQUISETACE^E Spores produced on the under side of the 



shields-shaped scales of a terminal spike or cone . 267 



LYCOPODIACEJE. Low, long-stemmed, moss-like ever- 

 greens. Spores-cases produced in the axils of 

 the simple leaves or bracts. Spores of one kind 

 only 269 



SELAGINELLACE^:. Spores of two kinds, large and small. 

 Spore-cases solitary in the axils of small 4-ranked 

 leaves, or at the bases of linear radical leaves. . . . 270 



SALVINIACE^E. Sporocarps beneath the stem. Floating 

 aquatics, pinnately branched, with minute imbri- 

 cated leaves. . 271 



