SERIES II. 



CRYPTOGAMOUS OR FLOWERLESS PLANTS. 



Vegetables destitute of proper flowers, and producing, 

 in the place of seeds, minute homogeneous bodies (spores) 

 containing no embryo. 



Class III.— Acrogens. 



Plants with a distinct stem, growing from the apex only, contain- 

 ing woody fiber and vessels. 



154. HORSETAIL FAMILY. Order, Equisetace^.. 



EQUISETUM, L. Scouring Rush. 



Character same as that of the order. Plants leafless, 

 simple stem or with whorled branches ; stems striate-sul- 

 cate, jointed, fistular between and separable at the joints; 

 sheaths dentate, crowning each internode; fructification 

 terminal, spiked or cone-like, composed of 6-sided peltate 

 scales arranged spirally, bearing beneath 4-7 spore-oases 

 which open laterally; spores globular, furnished at the base 

 with 4 club-shaped elaters (elastic filaments) involving 

 them spirally, or open when discharged. 



E. L^viGATUM. Tall, erect, simple or somewhat branch- 

 ed; sheaths elongated, appressed, green with black border, 

 of about 22 leaves ; sheaths of the branches about 8-leaved, 

 with subulate persistent points; stems 15-2° high. 



E. LiMOSUM. Stems somewhat branched, erect, striate- 

 sulcate; tranches from the middle joints, simple, short, 

 5-sicled, smooth; sjjihe oblong-ovoid; sheaths appressed. 

 Stem 2° high. Banks of Buffalo Bayou. 



