SERIES II. 



i 

 CRYPTOGAMOUS OR FLOWERLESS PLANTS. 



VEGETABLES destitute of proper flowers (i. e. having no 

 stamens nor pistils), and producing instead of seeds minute 

 one-celled germinating bodies called spores, in which there 

 is no embryo or rudimentary plantlet. 



CLASS III. ACROGENS. 



Cryptogamous plants with a distinct axis or stem, grow- 

 ing from the apex, and commonly not with later increase 

 in diameter, usually furnished with distinct leaves ; repro- 

 duction by antheridia and archegonia, sometimes also by 

 gemmation. 



SUBCLASS I. VASCULAR ACROGENS, OR PTERI- 

 DOPHYTES. 1 



Stems containing woody fibre and vessels (especially scalari- 

 form or spiral ducts). Antheridia or archegonia, or both, 

 formed on a minute prothallus which is developed from the 

 spore on germination, the archegonium containing a nucleus, 

 which after fertilization becomes an oospore and at length 

 grows into the conspicuous spore-bearing plant. 



ORDER 130. EQUISETACEJE. (HORSETAIL FAMILY.) 



Rush-like, often branching plants, with jointed and mostly hollow stems 

 from running rootstocks, having sheaths at the joints, and, when fertile, 

 terminated by the conical or spike-like fructification composed of shield- 

 shaped stalked scales bearing the spore-cases beneath. A single genus. 



1 The orders of this Subclass have been elaborated anew for this edition by 

 Prof. DANIEL C. EATON of Yale University. 



