MAXON—STUDIES OF TROPICAL AMERICAN FERNS. 549 
DIsTRIBUTION: British Honduras, eastern Guatemala, and Nicaragua, ascend- 
ing to 450 meters. Reported also from Costa Riea. 
ILLUSTRATION : Contr. U. S. Nat. Herb. 17: pl. 14. 
Polypodium mitchellae is most nearly related to P. shaferi, of Cuba, with 
which it was compared at the place of publication of the latter. The scale 
characters there given for it are, however, far from correct, having been taken 
from immature and broken scales. An examination of perfect material shows 
the scales of mature plants to be elongate-lanceolate to lance-ovate or some- 
times broadly ovate, long-acuminate or usually attenuate, 1 to 1.7 mm. long, 
0.36 to 0.63 mm. broad (excluding the long, divergent cilia). In form and 
dimensions, therefore, they approach those of P. shaferi, but their structure is 
different, the cells being broader and more irregular, with much thinner par- 
tition walls and much larger lumina. The two species are otherwise readily 
distinguishable by the characters previously pointed out. 
The following specimens are in the U. S. National Herbarium: 
GUATEMALA: Trunks of forest trees near Secanquim, Alta Verapaz, alt. 450 
meters, Maron & Hay 3195, 3213. 
11. Polypodium shaferi Maxon, Contr. U. S. Nat. Herb. 17: 410, 1913. 
TYPE LOCALITY: Near Camp La Gloria, south of Sierra Moa, Oriente, Cuba, 
among moss on roots and rocks (Shafer 8071). 
DISTRIBUTION: Known only from the. original specimens. 
ILLUSTRATION : Contr. U. S. Nat. Herb. 17: pl. 13. B. 
The position of P. shaferi, and especially its relationship to the last preceding 
species, were fully discussed at its place of publication. 
12. Polypodium schenckii Hieron. Hedwigia 44: 87. 1905. 
TYPE LOCALITY: Serra do Mar, near Joinville, Province of Santa Catharina, 
Brazil (Schenck 1248). . 
DISTRIBUTION: Known only from Brazil. 
As previously noted * Polypodium schenckti belongs undoubtedly to the group 
of P. trichomanoides rather than to that of “P. serrulatum” (P. duale), in 
which it was placed by Hieronymus. ° 
In addition to the material listed by Hieronymus the following specimens 
have been studied: 
Brazit: Joinville, State of Santa Catharina, alt. 1,000 meters, Schmalz 
(Rosenstock, no. 189). Without locality, Glaziou 7491. Caldas, Minas 
Geraés, Regnell III. 1462 * (received as P. peruvianum). 
13. Polypodium organense (Gardn.) Mett. Abh. Senckenb. Ges. Frankfurt 
2:39. 1857. 
Grammitis organensis Gardn. in Hook. Icon. Pl. 6: pl. 509. 1848. 
TYPE LocALITy: Ravine near the summit of the Organ Mountains, Brazil 
(Gardner 5918). 
DISTRIBUTION: Brazil. 
IntustRations: Hook. Icon. Pl. 6: pl. 509 3 Fée, Crypt. Vasc. Brés. 1: pl. 78. f. 1. 
A comparison of the scales of P. organense with those of P. schenckii sug- 
gests a much closer relationship between these two species than their pro- 
nounced differences in leaf form would indicate. The scales of P. schenckii 
have been described by Hieronymus. Those of P. organense are longer, broader, 
and similarly whitish-ciliate; the cells are arranged in 7 to 11 rows and the 
partition walls are much thicker, the lumen often obsolete. 
*Contr. U. S. Nat. Herb. 17: 406, 410. 1913. 
10069°—16——2 
