oe ee fag er pee ee 
SLosson: NOTES ON TWO NorTH AMERICAN FERNS 309 
broadest at base, bipinnate or rarely tripinnate; pinnae and 
pinnules alternate, not articulated at base, conspicuously stalked, 
diverging from the flexuose rachises at an angle of 45°-90°: basal 
pinnae with 2-5 divisions, uppermost pinnae often simple; ulti- 
mate divisions (pinnules) rather bright often bluish-green, mostly 
flabelliform from a narrowly cuneate base, the basal sides 
entire and often unequal, flaring and often recurving, the upper 
margin broadly rounded or rarely subdeltoid, cleft 4-1 of their 
depth into 1 or 2 lobes; lobes sometimes entire, usually once or 
more times slightly notched, between the notches usually com- 
pletely recurved to form the indusia but when sterile sharply 
denticulate; sterile pinnules flatter at base, often scarcely cuneate, 
otherwise similar to the fertile; apical pinnules the largest, up to 
2.5 cm. broad and 2 cm. long; veins flabellate-dichotomous, about 
5-7 times forked, the basal fork and the outer branches of the 
second fork often dark brown like the rachis and edging the leaflet’s 
base; texture firm; indusia heavy, up to 8.3 mm. long, subentire 
or erose; spores verrucose. 
Type in the Underwood Herbarium at the New York Botanical 
Garden, collected in the Armstrong Cafion, in southeastern Utah, 
altitude 1,600-1,800 meters, August 4-6, 1911, Rydberg & Garrett 
0423. Represented also by Rydberg & Garrett 9422. A fertile 
frond is shown on PLATE 7, FIG. I. 
Explanation of plate 7 
ag 1. Adiantum rimicola; fertile frond, natural size, Rydberg & Garrett, 9423. 
2-4. Trichomanes Petersii; 2, plant from Santo Domingo, X34, H. von 
ee 3066 in part; 3, fronds collected near Gadsden, Alabama, ie 14, Pollard 
& Maxon 353; 4, part of plant from Santo Domingo, much enlarged, H. von Tiirck- 
heim 3066 in part 
