572 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
partially sterile fronds of other collections are less scaly. The scales of the 
under side in all the fronds, however, are distinctive, 
Polypodium murorum is known from North America only upon Mr. Pittier’s 
single collection from an isolated and little explored part of Costa Rica, this 
having been reported upon by Christ? in 1901. 
The following specimens are in the U. S. National Herbarium: 
Costa Rica: El Piramo de Buena Vista, alt. 3,000 meters, Pittier 10485. 
Ecuapor: Without locality, Jameson; Couthouy. Cubillin, eastern Cordil- 
lera, alt. 2,400 meters, Rimbach (Rosenstock, no. 1a.). Rio Suguibf, 
western Cordillera, alt. 3,200 meters, Rimbach (Rosenstock, no. 34). 
Near Quito, alt. 2,800 to 3,300 meters, Lehmann 157. Near Yerbas 
Buenas, western Cordillera, alt. 2,600 to 3,300 meters, Lehmann 5726. 
16. Polypodium leucosticton Kunze, Linnaea 20: 380. 1847. 
Polypodium karwinskyanum A.Br.; Mett. Abh. Senckenb. Ges. Frankfurt 2: 
66. 1856, in part. 
Polypodium plebejum var. columbiense Kuhn, Abh, Naturf. Ges. Halle 11: 40. 
1869. 
Polypodium plebejum var. palmense Christ, Bull. Herb. Boiss. II. 5: 4. 1905. 
TYPE LOCALITY: Colombia. 
DISTRIBUTION: Mountains of Central America and northern South America, 
ascending to 2,300 meters, 
The present species, which was founded upon two separate collections from 
Colombia (iartweg 1499 and Moritz 836), has been discussed recently at some 
length by Hieronymus,? who appears to have somewhat enlarged its scope. 
In the absence of authentic specimens of the original collections the present 
writer can add little to Hieronymus’s treatment and will merely suggest 
that there are here included several forms which probably are specifically 
distinct. In order to distinguish these properly it will doubtless be necessary 
to assemble a large series of ample and well prepared specimens, which have 
been carefully selected in the field. Abraded, discolored, and incomplete mute- 
rial in this species is nearly worthless, because of the partial dimorphism of 
the fronds and the need of a full knowledge of the scale characters, Thus, 
partly upon this account, Hieronymus has been led into the error of citing 
Lehmann’s no. 640, from southern Colombia, as belonging to this species, 
whereas in its densely paleaceous under surface it is clearly distinct and pos- 
sibly represents an undescribed but closely related species. 
Christ * also has discussed the characters of P. leucosticton in referring to 
it his own P. plebejum var. palmense, founded upon two Costa Rican specimens 
(Tonduz 12571; Pittier 18257), and has cited additional Central American 
material. 
Kuhn’s P. plebejum var. columbiense is the exact equivalent of P. leucostic- 
ion, the name columbiense having been given merely as a new designation for 
leucosticton, when this form was reduced to varietal rank under P. plebejum, 
as Kuhn thought proper. 
Regarding P. leucosticton in the broad sense of Hieronymus and Christ, it 
may be distinguished from P. plebejwm not only by its plane or somewhat 
undulate (not crispate) rhizome scales, but also by its stouter and more or 
less alate stipes and usually by its subdimorphous fronds; that is, the sterile 
fronds are short-stipitate, the lamina commonly deltoid-oblong and relatively 
*In Pittier, Prim. Fl. Costar. 3: 14. 1901. 
* Bot Jahrb. Engler 34: 521. 1905. 
* Bull. Soc. Bot. Genéve II. 1: 219. 1909. 
