440 FILICE8. (TRUE FERNS.) 



segments, the lowest ones rarely diminished : veins branched into 3 or 4 vein- 

 lets, the lowest ones on the upper side of the vein bearing at their thickened 

 ends the subglobose sori midway between the midrib and the margin of the 

 segments. — From the Rocky Mountains eastward to the Atlantic ; also 

 westward. 



2. NOTHOL-5INA, R. Brown. 



In ours the fronds are 3 to 5-pinnate, and covered beneath with a white or 

 yellow powder, the primary and secondary pinnae distinctly stalked, and the 

 ultimate pinnules very small, oval or 2 to 3-lobed. 



1 • N. Fendleri, Kunze. Frond 2 to 5 inches long, broadly deltoid-ovate, 

 4 to 5-pinnate ; rhachis and all its branches flexuous and zigzag, the pinnae 

 alternate; ultimate pinnules 1 to 2 lines long. — From Colorado to Arizona 

 and Texas. In clefts of exposed rocks. 



N. dealbata, Kunze, reported near the eastern and southern limits of our 

 range, very likely occurs within it. It is closely allied to N. Fendleri, but 

 may be distinguished by its smaller fronds, w r hich are triangular-ovate and 

 3 or 4-pin nate, straight rhachis and branches, mostly opposite pinnae, and 

 ultimate pinnules hardly a line long. 



3. CHEILANTHES, Swartz. Lip-Fern. 



Small ferns, with 2 to 4-pinnate fronds, and the under surface either smooth 

 or variously covered with hair, wool, scales, or waxy powder. Ours belong to 

 the section in which the involucres are continuous around the greater part of 

 the margin of the very minute and bead-like ultimate segments, and the 

 lower surface of the fronds tomentose or scaly. 



* Fronds tomentose beneath, but not scaly. 



1. C. lanuginosa, Nutt. Fronds 2 to 4 inches long, ovate-lanceolate, tri- 

 pinnate or bipinnate with pinnatifid pinnules ; ultimate segments less than a 

 line long ; upper surface scantily tomentose, the lower surface matted with jointed 

 woolly hairs; involucres herbaceous, very narrow. — From Arizona and Colorado 

 to British America and eastward to Wisconsin and Illinois. Grows in dense 

 tufts on dry exposed rocks. 



2. C. Eatoni, Baker. Stalks with narrow scales as well as hairs : fronds 

 4 to 9 inches long, oblong-lanceolate, above woolly -pubescent, beneath matted-tomen- 

 tose and partly scaly, tripinnate ; ultimate segments $ line long, rounded obo- 

 vate ; margin continuously recurved, the edge membranaceous. — Colorado and 

 Arizona to Texas. 



* * Fronds very scaly beneath, tomentum scanty or none. 



3. C. Fendleri, Hook. Rootstock slender; its scales loose and nerve- 

 less: frond 3 to 6 inches long, tripinnate; ultimate pinnules rounded and 

 entire or obovate and 2 to 3-lobed, covered beneath with broadly ovate, acumi- 

 nate scales, which are sometimes sparingly ciliate at base. — From Colorado 

 to Arizona and Texas. In crevices of rocks. 



