LYCOPODIACE.E. 



[ 406 ] 



LYCOPODIACE^E. 



but their arrangement exhibits many curious 

 peculiarities. In PSILOTUM, one of the 

 simplest forms, where they are mere minute 

 scales on a widely bifurcated stem, they are 

 alternate; in some Lycopodia they are 

 opposite, in others whorled. When the 



Fig. 435. 



leaves are in whorls, they vary in number, 

 not only in different species, but often in the 

 same species in different localities, or even 

 in the same plant. Thus the arrangement 

 is often different on the main stem and on 

 the branches. 



Fig. 436. 



Fig. 437. 



Lycopodium phlegmaria. 



Fig. 435. Section of the stem. Magnified 50 diameters. 

 Fig. 436. The centre of ditto. Magnified 150 diameters. 

 Fig. 437. One of the isolated bundles of ditto. Magnified 200 diameters. 



When the leaves are opposite, those 

 forming the pairs sometimes differ both in 

 dimensions and form ; in Lycopodium 

 complanatum (fig. 438), the pairs of opposite 

 leaves cross alternately at right angles so as 

 to form four rows up the stemj in two 



Fig. 438. Fig 



(opposite) rows the leaves are alike and 

 flattened laterally; of the other two rows, one 

 consists of leaves like the two just described, 

 but flattened against the stem; and the 

 fourth row (opposite the third) of minute, 

 scale-like bodies. In other cases, in Selagi- 



439. 



Fig. 440. 



Fig. 438. Lycopodium complanatum. Young shoot. 



Fig. 439. Lycopodium lucidulum. Spike of fruit. Magnified 3 diameters. 



Fig. 440. Selaginella apoda. Young shoot. Magnified 2 diameters. 



