MAXON—STUDIES OF TROPICAL AMERICAN FERNS. 145 
Distrisution: Widely distributed in Mexico; also in Petén and Alta Verapaz, 
Guatemala. 
Asplenium palmeri is unique among the species of this group in the prolonged naked 
apices of its fronds, the ends proliferous, rooting, and often bearing young plants. 
The specimens examined have previously been cited. 
11. Asplenium extensum Fée, Mém. Foug. 7:51. 1857. 
TyprE. LocaALity: Ocafia, Colombia (Schlim 629). 
DistriputTion: Colombia and Peru. 
IntustraATION: Fée, loc. cit. pl. 13. f. 2, representing the type specimen. 
Although no specimens of Asplenium extensum have been seen by the writer, it is 
possible to here include this species because of its marked peculiarities, as shown by 
Fée’s very complete figures. Ithas been reported from Peru recently by Hieronymus,} 
though it appears to have been unknown to Sodiro? as occurring in Ecuador. Metten- 
ius has redescribed ? it upon the basis of Fée’s illustration. 
12. Asplenium castaneum Schlecht. & Cham. Linnaea 5: 611. 1830. 
Fieures 5, 6, 7. 
Asplenium rubinum Davenp. Bot. Gaz. 19: 391. 1894. 
Asplenium trichomanes var. castanea Hieron. Bot. Jahrb. Engler 34: 459. 1905. 
Typr Locatity: Mount Orizaba, Mexico (Schtede & Deppe). 
DistrisutTion: High mountains and volcanoes of Mexico and western Guatemala to 
Peru and Bolivia, ascending to 4,500 meters. 
The failure of Hooker and several later writers upon ferns to recognize Asplenium 
castaneum as a species amply distinct from A. trichomanes may be attributed partly 
to a want of complete material and in greater part to the prevalence of a different con- 
ception of species limits; but that this confusion should have persisted till now is 
rather remarkable. Thus, Asplenium trichomanes is mentioned by a recent American 
writer‘ as one of several species of the northeastern United States which extend far 
southward, this species in particular being found ‘‘above 3,350 meters” upon the 
Volcan de Fuego, Guatemala. Asplenium trichomanes, however, barely reaches 
northern Mexico, and the Guatemalan plant in question is A. castaneum. Recently 
also Hieronymus,® notwithstanding his exact and highly painstaking work upon the 
Pteridophyta in general, has regarded A. castaneum as a variety of A. trichomanes; 
although its greater size and more sturdy habit, as well as the delicate, large, brown 
scales of the rhizome, the very stout, fibrillose stipes, the large pinnz, and the very 
large and broad, erose indusia should suffice to differentiate it at once as a distinct 
species. 
Mr. Davenport, who was loth to describe new species, holding always to a very 
broad concept of specific limits, had no doubt of the distinctness of this plant, though 
he seems not to have known of the application of the name castaneum. In describing 
this species as A. rubinum he compares it with A. trichomanes, remarking that ‘‘once 
seen it is not likely to be mistaken for any other known species.’ The type of rubinum 
is Mr. Pringle’s no. 5191, from the Sierra de las Cruces, State of Mexico. This and Mr. 
Pringle’s no. 6150, collected later at the same locality, are perfectly characteristic of 
A. castaneum, and include plants of two different sorts: (1) Specimens which are stout 
and exceedingly fertile, the pinnee nearly medial in attachment and having usually 
4 or 5 pairs of crowded sori to each; and (2) others which are only partially fertile, having 
the pinne trapeziform-oblong in outline, mostly attached at the proximal point of 
1 Hedwigia 47: 223. 1908. 
2 Sodiro, Crypt. Vasc. Quit. 143. 1893. 
3 Abh. Senckenb. Ges. Frankfurt 3: 182. 1860. 
# Rhodora 10: 20. 1908. 
5 Bot. Jahrb. Engler 34: 459. 1905. 
