202 



A TEXT-BOOK OF BOTANY 



far more conspicuous plants than they are now, and only 

 the smaller forms have persisted to the present time. 



116. Strobili. One of the conspicuous features of the 

 lycopods is the cylindrical strobilus, which usually termi- 

 nates the erect branches, and is the "club" that enters into 

 the name club-moss (Fig. 193, A). Sometimes the strobilus 

 is quite distinct from the rest of the stem; and sometimes it 

 cannot be distinguished from it, so that there is no external 

 indication where leafy stem ends and strobilus begins. 



The leaves of the strobilus resemble the ordinary fo- 

 liage leaves; but each one is a sporophyll, bearing a single 

 large sporangium on its upper surface at the base (Fig. 193, 



B), so that the sporangium ap- 

 pears in the axil of the sporo- 

 phyll. Among the ferns the spo- 

 rangia are numerous on the under 

 side of leaves; among equisetums 

 they are several on the under side 

 of sporophylls; among lycopods 

 they are solitary on the upper 

 side of sporophylls. 



117. Lycopodium. The Lyco- 

 podium forms are chiefly the 

 coarse club-mosses of temperate 

 regions, and are mostly spoken of 

 as the large club-mosses. The 

 strobili are often conspicuous and 

 very distinct from the rest of 

 the plant. This leafy, branching 

 plant with its strobili is, of course, 

 the sporophyte (Fig. 193, A). 

 When its spores germinate they 



rkrnr | nr o-arnAf nrJiirf AC Vmf fVi^GA 

 P F< 3 gametOpnyteS, t 



instead of being 

 sou. After BRUCHMANN. green, prostrate, thallose bodies, 



FIG. 194. Subterranean gam- 

 etophytes of Lycopodium, 

 showing their irregular, tu- 

 berous form; the dotted line frametophvtes 

 represents the surface of the * 



