iMAXON—STUDIES OF TROPICAL AMERICAN FERNS, 589 
group, frora all of which it differs in its mostly closed venation and in scale 
structure. 
This is not improbably the species described and illustrated by Hooker and 
Greville as Pleopeltis pinnatifida, upon specimens collected upon the Cerro del 
Morro, Sar Luis, Argentina, by Gillies. These have not been examined by the 
writer. They came from the region of P. argentinum and, as illustrated, agree 
closely with the Lorentz specimens in general appearance. Their venation and 
minute scale characters are not described. Pleopeltis pinnatifida can, there- 
fore, be cited at present only as a probable synonym of P. argentinum, The 
earlier Polypodium pinnatifidum of Gilibert,”1792, would in any event preclude 
the transfer of Pleopeltis pinnatifida to Polypodium for this plant. 
8. Polypodium leucosporum Klotzsch, Linnaea 20: 404. 1847. 
Pleopeltis leucospora Moore, Ind. Fil. LXXVII. 1857. 
Lepicystis leucospora Diels in Engl. & Prantl, Pflanzenfam. 1*: 324. 1897, 
TYPE LOCALITY: Mérida, Colombia (Moritz 306). 
Distripution : Mountains of Colombia and Venezuela. 
This is a peculiar species which has been redescribed by Mettenius,”? Hooker,” 
and Hooker and Baker,’ always rather inadequately and without indication 
of its true affinities. Thus Diels,‘ including it in the genus Lepicystis, places 
it in his section Phlebolepicystis, as a member of the P. lanceolatum group, 
which is essentially the alliance suggested by Mettenius. It seems to the writer 
that, notwithstanding the subphlebodioid venation, the relationship is rather with 
P. thyssanolepis. The single specimen in the U. S. National Herbarium (Leh- 
mann 580, from Pasto, southern Colombia, altitude 2,544 meters, February 28, 
1881) was in fact so determined by Hieronymus,’ an error which though obvious 
enough is accounted for by the general similarity of these two species and the 
fact that the Lehmann plants of P. lewcosporum are more regularly pinnatifid 
and more symmetrical than those of the type collection. The latter are known 
to the writer from a sketch, and from a single slightly lobate frond in the 
Underwocd Herbarium, which in scale and sorus characters agree essentially 
with the Lehmann plants, differing only in the shape of the frond. Diels has 
suggested that P. lewcosporum is perhaps an abnormal state of P. lanceolatum 
L., a simple-leaved species which does occasionally produce lobate fronds (the 
variety elizabethae Jenman) > but this supposition is readily disproved by an 
examination of the rhizome and lamina scales. 
Chiefly from the new Lehmann material, therefore, P. lewcosporum, which is 
believed normally to have regularly and deeply pinnatfid fronds, may be 
redescribed as follows: 
Rhizome short-creeping, the few branches 2 to 5 cm, long, about 2 mm. in 
diameter, radicose beneath, densely covered with oblique or laxly appressed, 
widely imbricate scales, these 3 to 5 mm, long, narrowly oblong-lanceolate, 
long-attenuate, attached far above the rounded base, light brown in mass, 
picolorous singly, the dark brown lance-attenuate median line extending nearly 
‘to the apex (the cells of this short to linear-oblong, subquadrate to hexagonal, 
with strcngly sclerotic dark brown partition walls and hyaline outer walls, an 
1 Abh. Senckenb. Ges. Frankfurt 2: 89. 1856. 
2Sp. Fil. 5: 76. 1864. 
* Syn. Fil. 362. 1868. 
‘Engl. & Prantl, Pflanzenfam. 1‘: 324. 1897. 
® Bot. Jahrb. Engler 34: 531. 1905. 
® Bull. Bot. Dept. Jamaica II. 4: 199. 1897. 
