BOTANY. 
161 
as a general resemblance to A. rigidum, Sw. The sori are as large as in A. marginale. 
When young, the stipe and rachis are thickly clothed with chaffy scales. 
Aspidium aculeatum, Swartz; Hook. FI. Bor.-Am. 2, p. 261 ; Torr. FI. N. York , 2 ,p. 498. 
Deep ravines, Napa Valley, California. Some of our specimens agree better with A. lobatum 
than with A. aculeatum ; but we fully agree with Hooker, that these and A. angulare con¬ 
stitute but one species. Kutzing thinks that a part, at least, of the North American forms of 
A. aculeatum should be referred to A. (Polystichum) Braunii, Spenn. FI. Frib. 
SALVINIACEiE. 
Azolla Caroliniana, Willd . Sp. 5 ,p. 541; Torr. FI. N. York, 2 , p. 513. A. microphylla, 
Kaulf.; Hook. & Am. Bot. Beech, p. 162. On the surface of slow-flowing or stagnant waters, 
Western New Mexico and California. 
