1920]  Weatherby,—Varieties of Pityrogramma triangularis | 115 
The descriptive key which follows will serve to indicate the dis- 
tinguishing characters of the three varieties here recognized. "They 
include nearly all the plants which have hitherto passed as white- 
powdered forms of P. triangularis. True P. triangularis with white 
indument appears to be rare, as one would expect in the case of an 
albino form. Except as noted under var. viscosa, the size and cutting 
of the lamina covers an essentially similar range of variation in all 
the varieties, though with more or less marked tendencies toward a 
certain type in each and a consequent difference of aspect much more 
easily seen than described. 
I have had the privilege of examining in addition to the specimens 
in the Gray Herbarium, the material in the United States National 
Herbarium, the herbaria of Yale and Leland Stanford Universities 
and the Philadelphia Academy of Natural Sciences. For this valu- 
able opportunity I am indebted to the authorities of these institu- 
tions. I am also under special obligation to Rev. George L. Moxley 
for procuring for me living plants of var. viscosa, to Mr. Bayard Long 
for needed information on various matters and to Mr. William R. 
Maxon for encouragement and helpful criticism throughout. I take 
pleasure in dedicating one of the segregates here described as new to 
Mr. Maxon, as some small evidence, if it may pass as such, partly 
of personal gratitude for many courtesies received, but still more of 
the appreciation of his admirable work which all fern-students must 
feel. 
A. Upper surface of the usually coriaceous lamina glabrous; stipe usually 
bright red-brown and shining in young fronds, turning darker with age, 
essentially glabrous; indument bright to pale yellow, rarely white or 
lacking; basal segments of the lowest pinnae usually elongate and pinna- 
tifid; spores round to deltoid in outline............ 1. P. triangularis 
A. Upper surface of the lamina glandular or viscid or both; indument white, 
rarely pale yellow or lacking 
B. Upper surface of the usually coriaceous lamina viscid, often also with 
yellowish, stalked, resinous glands; stipe red-brown, essentially gla- 
brous; lower basal segments of the lowest pinnae usually only undu- 
late-crenate, not pinnatifid; spores round to deltoid in outline; plant 
of southwestern California... . 1... nc 220 5L var. viscosa 
B. Upper surface of the often rather thin lamina glandular only, not viscid; 
lower basal segments of the lowest pinnae usually elongate, dilated 
and deeply pinnatifid. 
C. Stipes mostly blackish and glandular and white-farinose above and 
near the base, not very lustrous; lamina thin and soft, usually 
1Indicated in the citation of specimens by the following symbols: Gray Herb., 
G; U. S. National Herb., N; Herb. Phil Acad., P; Herb. Stanford Univ., S; Herb, 
Yale Univ., Y. 
