XXIV KEY TO THF. ORDERS. 



III. GLUMACEOUS DIVISION. 



Flowers without a true perianth, but subtended by thin 

 scales called glumes. 



Cyperace^. — Sheaths of the leaves not split -. 248 



GRAMINE.B. — 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. I 



CLASS III. PTERIDOPHYTES. 



v 

 Stem containing vascular as well as cellular tissue. 



FiucES. — Spores produced on the fronds ; 2.57 



Equisetace^ — Spores produced on the under side of the f 



shield-shaped scales of a terminal spike or con^ 267 



Lycopodiace^. — Low, long-stemmed, moss-like ever- \ ^ 

 greens. Spores-cases produced in th.&'axils of V 

 the simple leaves or bracts. Spores of one kind . : 

 only .^ 260" 



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 



Sai.viniace^. — Sporocarps beneath the stem. Floating 

 aquatics, pinnately branched, with minute imbri- 

 cated leaves , . . . 271 



