MAXON—STUDIES OF TROPICAL AMERICAN FERNS. 579 
7. PotypopruM PLATYBASIS Baker in Hook. & Baker, Syn. Fil. ed. 2. 511. 1874. 
The present species, which was founded upon specimens collected near Salta, 
in the Andes of northwestern Argentina, by Pearce, seems from description to 
be related to P. monosorum and P. murorum. Christensen,’ however, lists it 
as belonging to the subgenus Goniophlebium and as occurring in Guatemala, 
but upon what ground in either particular is not clear. It has not been seen 
by the writer. 
8. PorypopIuM PLEOPELTIDIS Fée, Crypt. Vasc. Brés. 1: 86. pl. 26. f. 1. 1869. 
This species, which is known to the writer only from Fée’s illustrations, was 
founded upon two Brazilian numbers collected by Glaziou (2459, 2817). It is 
referred by Christensen to P. plebejum, a species which it obviously resembles 
but which does not extend south of Panama, so far as the writer can find. 
Judging from the figures, P. pleopeltidis is more nearly related to certain of 
the forms included by Hieronymus in P. leucosticton. 
9, PoLYPODIUM SEGREGATUM Baker in Hook. & Baker, Syn. Fil. ed. 2. 510, 1874. 
An Ecuadorean species, recognized by Christensen, founded upon plants 
collected in the Andes of Quito by Jameson. Not known to the writer. 
10. PotypoprumM TUERCKHEIMI Christ, Bull. Herb. Boiss, II. 5: 254, 1905. 
This, which was founded upon a single collection made by von Tiirckheim at 
Cubilquitz, Alta Verapaz, Guatemala, altitude 350 meters, and distributed by 
Capt. John Donnell Smith under no. 7721, is said by Christ to be exactly inter- 
mediate between P. fallar and P. lindenianum. It is unknown to the writer. 
POLYPODIUM SQUAMATUM AND ITS ALLIES. 
The grounds for referring Lepicystis to Polypodium have already 
been discussed briefly (p. 557). The present notes relate to the 
tropical American species with pinnatifid to pinnatisect lepidote 
fronds and more or less typical goniophlebicid venation. Polypo- 
dium squamatum and P. lepidopteris are representative of this group. 
While the extremes in both character and amount of scaly covering 
are not so great as in the group of free-veined lepidote species, the 
actual characters of scale structure are for the most part precise and 
sufficiently obvious to afford good recognition marks for the species. 
Of the 17 species here recognized 5 are described as new, and several, 
previously little known, are reinstated. Three doubtful species also 
are mentioned. 
KEY TO THE SPECIES. 
Rhizome scales small, roundish to triangular-ovate, 
brownish fuscous, very closely appressed, contigu- 
ous or subimbricate. ; 
Segments 3 to 6 (rarely 8) mm. broad; lower surfaces 
brown from the presence of very numerous 
contiguous or imbricate scales. 
Sori 8 to 14 pairs, deeply immersed, the upper 
surface of the segment strongly embossed. 1. P. myriolepis. 
Sori 20 to 30 pairs, nearly superficial. .......-..- 2. P. sanctae-rosae. 
Segments 9 to 13 mm. broad; lower surfaces green, 
bearing numerous distant minute roundish 
scales. 2.22.2... 0222 e eee ee ee eee 3. P. collinsii, 
*Ind, Fil. 555. 1906, 
