ERRATA. 



Page 4, line 19, for Sporangir read Sporangia. 

 "' '"^ *^ 34-, '^ contral '^ revti'al. 



- 6, '^ ^), - CHETLATHES i'^2.(\ CTIEILANTHES. 



"' '/, '' 21, '' rein /fonn. yi-'2id I'e^i [form. 



Cryptogamous or Flowerless Plants. 



Plants destitute of true floral organs and having instead of 

 seed minute bodies called spores. 



PTJEBIDOPHYTA COHN. 



Vascular acrogens containiog woody tissue in the stems. 

 Sexual organs consisting of antheridia and archegonia formed 

 on a prothallus which is developed from a spore on germination, 

 and upon which an asexual plant is produced. 



OrderI. EQUISETACEAE DC. 



Rush like plants with jointed hollow stems and perennial 

 jointed running roots. Leaves represented by small sheaths at 

 joints or a short spike terminating the stem. Prothallus above 

 ground, green, usually lobed and dioecious. 



EQUISETUM L. Horse-tail. Scouring- rush. 



Stems simple, sometimes with short whorled branches near 

 the nodes, erect, hollow except at the nodes. Surface marked 

 lengthwise with alternate ridges and furrows. The cuticle fre- 

 quently containing silica. Spore cases 5 — 6, situated on the 

 under side of an angled shield like scale of the spike, one celled, 

 opening down the inner side. Spores numerous. 



* Stems annual of two Tcinds^ fertile and sterile^ fruiting in 

 the spring. 



E. ARVENSB L. Fertile stems pale or brownish 4—10 inches 

 high, appearing before the sterile, unbranched, soon perishing. 

 Sheaths large, with about 12 acuminate brown teeth. Sterile 



