175 



in open or partially shaded situations from the sea-level to about 

 5,000 feet altitude. Dr. J. K. Small [Tokkeva 3 : 141. 1903] 

 reports it " from sea-level to almost 4,000 feet altitude on the 

 eastern slopes of the Blue Rid^je. * * * It is confined to trees 

 only when rocks are lackin^^" Mr. C. L. Pollard [Plant World 

 5: 133. 1902] records a locality discovered by Mr. W. P. 

 Hay, near the Potomac River and within fifteen miles of Wash- 

 ington, D. C. ; this is possibly the most northern locality 

 known for this fern. This little colony of plants, from which the 

 figured specimen was taken, grows on a steep rocky slope ; it 

 consists of numerous plants matted together and covering many 

 square feet of surface. In this respect it differs from another of 

 the rock-loving ferns, Chcilanthes lanosa, which forms small clus- 

 ters along the fissures of the rocks. 



Our specimen is of interest also on account of its forking 

 frond — a rare phenomenon in this species — which, may I state 

 it, holds its own in beauty. ChcilantJies lanosa may possibly 

 excel it as an ornament in its native haunts. 



Washington, D. C. 



THE ARTIFICIAL INDUCTION OF LEAF FORMA- 

 TION IN THE OCOTILLO* 



By Francis E. Lloyd 



The post-pluvial appearance of foliage within a very short time 

 upon desert plants which remain through periods of drought in 

 a leafless condition is a phenomenon which has very often been 

 remarked. The behavior in this regard is most striking in deserts, 

 where there is prolonged lack of rain. Although in some regions 

 the rain penetrates into the ground very rapidly, nevertheless it 

 has seemed improbable to many, no doubt, that the absorption 

 of this water from the soil alone gives the necessary stimulus to 

 leaf formation. Led by this idea, attempts have been made to 

 find in many of the superficial structures of plants the means for 

 the absorption of water, or water vapor, and it may ver}' well be 



*This work was clone at the Desert Botanical Laboratory, Tucson, .\rizona, under 

 a grant from the Carnegie Institution, of Washington, during the summer of 1905. 



