MAXON—STUDIES OF TROPICAL AMERICAN FERNS. 581 
Scales of the lower surface of 
segments very numerous, 
oblique, forming a thick 
covering; rhizome scales 
linear-deltoid, attenuate, 
bright castaneous, concolor- 
0) 12. P. bombycinum. 
Scales of the lower surfaces 
fewer, closely appressed, 
imbricate, forming a thin 
covering, pale castaneous, 
the margins lighter........ 13. P. balaonense. 
Lamina not gradually long-attenu- 
ate from the middle, but nar- 
rowed (if at all) rather abruptly 
in the basal third. 
Rhizome scales small, bristle-like, 
rigidly divergent, abruptly 
attenuate-acicular from a mi- 
nute, roundish, appressed 
base... 2... eeee eee eee eee 14, P. pyrrholepis. 
Rhizome scales larger, widely im- 
bricate, oblique or appressed, 
either linear-deltoid and at- 
tenuate or ovate-acuminate 
and gradually long-attenuate. 
Sori superficial, the upper side 
of the segments not at all 
embossed. ........------- 15. P. roset. 
Sori somewhat impressed, the 
segments distinctly em- 
bossed above. 
Scales of the lower side of the 
segments very slender, 
imbricate, but forming a 
thin covering.....--.... 16. P. squamatum. 
Scales of the lower side much 
broader, more numerous, 
widely imbricate, form- 
ing a very dense thick 
covering.........-.-2+-- 17. P. fimbriatum. 
1. Polypodium myriolepis Christ, Bull. Soc. Bot. Belg. 35: 224. 1896; Bull. 
Herb. Boiss. 4: 661. October, 1896. 
Polypodium costaricanum Hieron. Bot. Jahrb. Engler 34: 530. 1904, not P. 
costaricense Christ, 1896. 
Polypodium wendlandii Hieron. Hedwigia 44: 180. 1905. 
TYPE LOCALITY: La Palma, Costa Rica, altitude 1,500 to 1,700 meters (T’'onduz 
9692). 
DistTRIBUTION: Mountains of Costa Rica and western Panama, at 1,300 to 
2,000 meters altitude. 
The normenclatorial history of this species has been rather confusing. In the 
first place, it was described as new twice by Christ in the same year under the 
same nanie, the order of publication probably being as above indicated. In 
10039°—16——-4 , 
