342 THE LYCOPODIALES 



club-like strobili or cones (Fig. 236) . The gametophyte or sexual 

 generation is also suggestive of the mosses. Particularly is this 

 true of the male gamete, which is small and not spirally coiled 

 and it is apparently biciliate (Fig. 240). 



The Lycopodiales are largely tropical, though a small number 

 of forms are of common occurrence in temperate regions. The 

 stems are erect or creeping and rather small, but owing to their 

 prolonged growth and extensive branching they often form con- 



FlG. 237. Cross-section of a portion of the stem of Lycopodium, showing 

 the centrally arranged vascular bundles. 



spicuous and attractive colonies. The tissues of the stem do 

 not materially differ from those of the common fern, though the 

 vascular bundles from the leaves generally unite in the stem to 

 form a central core of xylem surrounded by phloem. This 

 solid core of xylem may be broken up in various ways by the 

 development in it of masses of pith-like cells. Sometimes these 

 pith cells form plates alternating with the xylem (Fig. 237). 

 The work performed by the leaves, as in the Equisetales, is 

 usually of two kinds, namely, photosynthesis by the green foliage 

 leaves and spore production by the leaves that usually form 



