MAXON—STUDIES OF TROPICAL AMERICAN 
Scales of the rhizome with bristle-like cilia. 
Lamina pinnately lobed about halfway to 
the rachis........0.....0....2ee ees 18. P. 
Lamina pinnatifid to subpinnatisect. 
Vein of the fertile segments forked at or 
very near its middle. 
Rhizome stout, the scales linear, 1.5 
to 3 mm. long; lamina up to 
15 cm. long, pinnatifid, the 
segments joined by a broadish 
Rhizome small, the scales lance- ° 
oblong, 1 mm. long or less; 
lamina not exceeding 8 cm., 
subpinnatisect. 
Segments more than their width 
apart, oblique, long-de- 
current, freely setose, the 
hairs up to 1 mm. long.. 20. P. 
Segments less than their width 
apart, spreading, not de- 
current, less strongly 
setose, the hairs much 
shorter..............026- 21. P. 
Vein of the fertile segments forked dis- 
tinctly below its middle, com- 
monly in the basal fourth. 
Cilia of the rhizome scales hyaline.... 22. P. 
Cilia of the rhizome scales reddish 
brown. 
Segments very oblique, long-decur- 
rent; rhizome scales minute, 
with few cilia................-- 23. P. 
Segments spreading; scales much 
larger, freely ciliate. 
Soriferous veinlet of fertile seg- 
ments at least half as long as 
the sterile; segments dis- 
tinctly joined......... .-... 24, P. 
Soriferous veinlet of fertile seg- 
ments one-third to one-fifth 
as long as the sterile; seg- 
ments scarcely or not at all 
joined. 
Lamina conspicuously setose 
beneath, especially among 
the sporangia; annulus 15 
or 16-celled............. 25. P. 
Lamina scantily setose be- 
neath, the hairs shorter 
and more slender; an- 
nulus 13 or 14-celled..... 26. P. 
FERNS. 
andinum. 
. truncicola. 
nanum. 
daguense. 
hyalinum. 
setulosum, 
nimbatum, 
blepharodes. 
taenifolium, 
545 
