272 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
“pubescenti-hirsutis”’ or of veins “basi nigricantes,”’ nor does the illustration show 
ciliate margins. Otherwise the descriptions agree. Regla, which is not on most 
maps, is not far from Pachuca, Hidalgo, but at a somewhat lower altitude. 
Polypodium biserratum Mart. & Gal. T can but regard as a synonym of P. subpeti- 
olatiuin, It was described from Galleoti’s no, 6410, said to have been found in humid, 
cool situations in the eastern cordillera of Oaxaca, in the zone of vegetation ranging 
from 2,000 to 2,300 meters in altitude. 
Specimens examined: 
Michoacan: Hills of Patzcuaro, on trees and rocks, November, 1890, C. G. Prin- 
gle, no. 8828 (N, E, G, M—2 sheets, 8, U, as P. subpetiolatum). 
Federal District: Forest near San Nicolas, Bourgeau, July, 1866, no. 1038 (N, E, 
G, as P. biserratiun). 
San Luis Potosi: Near city of San Luis Potosi, W. Schaffner, October, 1879 (U). 
An examination of the fine series of Mr, Pringle’s 3328 shows a high degree of 
variability. Fournier? listed sxhpetiolatum and biserratum separately, noting that 
the former ‘‘differt a P. biserrato frondulis angustioribus, soris approximatis;’? and 
even Hooker ¢ in uniting them was inclined to shift responsibility upon Mettenius. 
It is not difficult to understand how, from insufficient material, Fournier’s view may 
appear correct, but it seems pretty plain, upon examination of the series of Mr. 
Pringle’s 3328, that the term hiserratiin has been applied to the more or less infertile 
states of true suhpetiolatum. For example, the Bourgeau specimens (no. 1038), 
labeled biserratum agree well with the less fertile and (consequently) more leafy 
ope 
individuals of 3328; yet the more perfectly fertile fronds of 3828 would be referred 
without question to subpetiolatum. Nor is 8328¢ separable into two forms: the very 
considerable variation extends by slight gradations from the symmetrical fertile 
type, figured by Hooker as subpetiolatum, to the leafy, irregularly serrate sort 
referred to by Fournier and others as biserrateon and rather diagrammatically figured in 
the original publication of the species. There is, indeed, a no greater amount. of 
variation here than is to be observed in many or perhaps a majority of the familiar 
ferns of the eastern United States, whose tendencies toward variability in certain 
directions are well known and recognized. In general, the more fertile the frond 
the more approximate are the sori and the less the degree of serration. Marked 
fertility is usually accompanied also by a loss of foliar tissue. The present case fur- 
nishes an excellent illustration. The Hookerian figure is a good representation of 
normally fertile subpetiolatum, except that the margin is not often so evenly serrulate, 
but shows usually an unmistakable tendency toward double serration. The figure 
shows rather more pubescence than is to be seen on the specimens cited above, In 
these the pubescence is mostly confined to both sides of the midyeins of the pinne, 
On the underside it is rather lighter in color, longer and less matted than above, 
and extends only very sparingly or not at all along the veinlets. P. biserration was 
originally described as glabrous; but no known member of the subpetiolatum group is 
absolutely without pubescence. In the several new species here proposed the 
quality and disposition of the pubescence have seemed valid diagnostic characters. 
Polypodium schaffneri Fée @ is often cited as a synonym of P. subpetiolatum, but a 
description seems never to have been published. The name alone was offered by 
@Mem, Acad. Brux. 155: 38. pl. a f. 1. da, 1842, 
» Mex. Pl. 78. 1872. 
eSp. Fil. 4: 220. 1862. 
“The rootstock, about 8 mm. thick, is densely clothed with delicate, glossy, 
irregularly ovate, imbricated scales, attached by their middle, of a mummy-brown 
verging to walnut-brown as they become long-attenuate at the base of the promi- 
nently jointed stipes. The rootstock of none of the specimens here cited under 
P. subpetiolatum shows any variation in this particular. 
eg™ Mem. 22. 1857, 
