CRYPTOGAMOUS OK FLOWERLESS PLANTS. 



499 



Series 11. Crtptogamous or Floweeless Plants. 



Plants destitute of proper flowers (stamens and pistils), and 

 propagated by spores instead of seeds. 



Class III. AcROGENOus Plants.* 



Vegetables with a distinct axis, growing from the apex, with no 

 provision for subsequent increase in diameter (containing woody and 

 vascular tissue), and usually with distinct foliage. 



961. Ord. EquisetaceSB {Horsetail Family). Leafless plants ; with 

 striated, jointed, simple or ^^^ ^^^ 



branched stems (containing ducts 

 and some spiral vessels), which 

 are hollow and closed at the 

 joints ; each joint terrfiinating in 

 a toothed slieath, which surrounds 

 the base of the one above it. In- 

 florescence consisting of peltate 

 scales crowded in a terminal 

 spike, or kind of strobile : each 

 with several thecce attached to its 

 lower surface, longitudinally de- 

 hiscent. Spores numerous, with 

 four elastic club-shaped bodies 

 (of unknown use), wrapped 

 around them when moist, or 

 spreading when dry. — Ex. Equi- 

 setum. The epidermis of Equi- 

 setum hyemale (the well-known 

 Scouring Rush) contains so much 

 silex that it is used for polishing. 



* For illustrations of Classes III. and IV. see the plates of Manual of the 

 Botany of the Northern United States. 



FIG. 1281. Summit of the stem of Equisetum sylvaticum. 1282. Part of the axis of the 

 fructification, with some of the fruit-bearing organs, shown magnified in Fig. 1283, a view from 

 underneath. 1284. A separate theca, or spore-case, more magnified. 1285, 1286. Spores, with 

 the club-shaped appendages more magnified. 



