GROUP III. PTERIDOPHYTA : LYCQPODINJB, 



421 



CLASS VII. 



SUB-CLASS HOMOSPOBE^E. 



Order 1. Lycopodiaceae. This order contains the two genera Lyeopodium 

 and Phylloglossutn : the former is a large genus, six species being British (L. 

 Selago, inundatum, annotinum, clavatum, alpinum, complanatum) and commonly 

 termed Club-mosses : the genus Phylloglossum has a single species (P. Drum- 

 mondii) found in Australia and New Zealand. 



THE SPOEOPHYTE. The stem. In Lyeopodium the stem is slender and much 

 branched, erect (e.g. L. Selago), or growing horizontally on the surface of the 

 ground (e.g. L. clavatam [Fig. 274] annotinum), or beneath the surface as a 

 rhizome (e.g. L. alpinum, complanatum) : the branching is in some cases dicho- 

 tomous, in others 

 monopodial : it 

 may take place 

 in all directions 

 or in one plane 

 only (L. complan- 

 atum). 



In Phylloglos- 

 sum the stem 

 (protocorm) is a 

 tuber, bearing an 

 apical tuft of 

 leaves : the only 

 branch formed 

 developes into 

 next year's tuber. 



The leaves. In 

 some species of 

 Lyeopodium all 

 the leaves are 

 alike (e.g. L. Se- 

 lago) ; but in 

 most species, as 

 also in Phyllo- 

 glossum, the foliage-leaves and the sporophylls are more or less widely different. 



The foliage-leaves are small and very numerous in Lyeopodium ; their 

 arrangement is various, whorled, or spiral, or in decussate opposite pairs (L, 

 complanatum, etc.) : in the last case there is beterophylly, as the decussate 

 leaves on the flattened sterile shoots vary in size, those on tbe lateral margins 

 of the shoots being larger than those on the flattened surfaces. The leaves are 

 sessile, simple, and have a rudimentary midrib. 



In Phylloglossum the foliage-leaves are few (3-7) ; they are sessile, simple, 

 somewhat awl-shaped, and about half an inch long. 



The sporophylls present considerable variety. In L. Selogo and its allies they 

 are quite like the foliage-leaves ; in most species of Lyeopodium (e.g. L. inundatum, 



FIG. 274. Portion of Lyeopodium, clavatum, somewhat smaller 

 than nat. size : s, the cone-like flower. B a single sporophyll (b) 

 from the cone, bearing a sporangium sp, which has dehisced ( x 10). 



