THE PLANT WORIvD 187 



to withstand drought, just as the liverwort, although this delicate struc- 

 ture is ordinarily supposed to be entirely dependent on a constant supply 

 of moisture. Thus, for example, the prothallia of a Gyninogravivie have 

 been allowed by Dr. Pierce to remain quite dry during an entire summer, 

 and, when moistened, they resumed their growth. 



There is evidently in these little plants an abundant opportunity for 

 a great deal of interesting observation and study. 



FOSSIL FUNGI. 



It appears highly probable that the peculiar structures found in cer- 

 tain fossil rootlets from the English coal measures, and described by F. E. 

 Weiss,* are the preserved remains of a mycorrhizal form, so that we may 

 be fairly certain that the symbiotic condition dates as far back as the 

 Carboniferous. This fact is instructive not alone in itself, but as an illus- 

 tration of the value of refined methods as applied to the study of fossil 

 remains. 



The same author describes a parasitic fungus which is found in the 

 rootlets of Stigmaria,'\ the giant lycopod root type. 



A CARNIVOROUS GALL. 



A CURIOUS gall, induced on an oak iQuercus leptobalamis) by a Cy- 

 nips, has been described by an Italian botanist, Mattei. The surface of 

 the gall produces two kinds of hairs — those which, as the author suggests, 

 are active in secreting a viscous material that catches small insects, after 

 the manner of the secretions on Drosera leaves, and those which have 

 the form of a four-armed star, similar apparently to the hairs in the traps of 

 Utriailaria. These are supposed to absorb the materials resulting 

 from the digestion of the small animal forms captured. It would 

 seem, therefore, that this gall is analogous to the leaves and traps of the 

 carnivorous plants, though the real significance of the matter is at present 

 not settled. 



Book Reviews. 



Harriman Alaska Expedition. Vol. V. Cryptogamic Botany. Pp. 

 404, 44 plates. New York : Doubleday, Page & Co. 



The first of the volumes devoted to the botanical fruits of this remark- 

 able expedition has been awaited with much interest, and an examina- 

 tion of the pages is calculated to arouse wonder at the scarcity of crypto- 

 gamic material obtained by previous collectors. For example, only 15 

 fungi had been hitherto reported from the whole of Alaska, whereas the 



* Annals of Botany, 18: 255, April, 1904. \The New Phytologist,i: 63, March, 1904. 



