100 



THE FERN BULLETIN 



sents any definite mode of outline or cutting. In our 

 own flora, simple and entire fronds are the exception, 

 but if we search the world over we shall find that such 

 species are not as rare as the study of our own flora 

 may have led us to think ; in fact, there are few genera 

 without at least one or two of these simple-fronded 

 species. In large works devoted to the ferns it is 

 customary to arrange the species in the order of their 

 cutting, the simple fronds coming first, then those that 

 are pinnatifid, then pinnate and so on. Each group 

 has much in common, and the species are more closely 

 related among themselves than they are to the rest 

 of the genus, but there are usually connecting links to 

 join one group with another. 



In the genus Poly podium, if we exclude the species 

 usually placed in the section or genus Phcgoptevis, the 

 fronds as a rule are not very extensively divided, 

 nevertheless there are not a very large number with 

 simple fronds. One of this number we have chosen for 

 illustration. It derives its specific name gramincum 

 or grass-like from the narrow fronds which are not 

 unlike blades of grass in shape and size. It is most 

 abundant in the elevated parts of Jamaica where it 

 grows on the branches of trees often many feet from 

 the ground. According to Jenman it may be distin- 

 guished from the species that resemble it by its hori- 

 zontal root-stock, distinct stipes and median sori. 

 Like so many of the Polypodiums its sori are some- 

 what oblong instead of round. 



Owing to the fact that it grows on trees at a dis- 

 tance from the earth and depends upon the rains for 

 its moisture it cannot grow in regions where rains are 

 not abundant and comparatively frequent, though, like 



