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SCIENCE 



[N. S. Vol. XXV. No. 634 



Canada. Its attacks are confined to the 

 leaves. It develops at the same season and 

 under generally similar conditions to the 

 well-known early and late blight fungi 

 (Alternaria solani and Phytophthora in- 

 festans) and bears so close a resemblance in 

 gross appearance to these that it has prob- 

 ably been commonly overlooked or con- 

 fused with these diseases. Its cultural 

 characters have been studied in detail. On 

 artificial media it produces only a resting 

 form of chlamydospore, similar to that pro- 

 duced in dead potato leaves. It is believed 

 that the usual spraying methods will hold 

 it in check. Certain varieties of potatoes 

 show well marked resistance to this fungus. 

 A detailed account of these studies will ap- 

 pear in the forthcoming (1906) report of 

 the Vermont Experiment Station. 



A Bibliography of NoHh American Lichen- 

 ology: Professor Bruce Fink, Miami 

 University. 



The paper attempts to give all titles 

 pertaining to North American lichenology, 

 from the first certain statement regarding 

 our lichens, about the beginning of the 

 eighteenth century, to the present time, 

 completing a preliminary announcement 

 concerning the bibliography made in 'Two 

 Centuries of North American Lichenology, ' 

 Proc. la. Acad. Sci., 1-38, 1904. With 

 each title appear explanatory notes as to 

 contents. 



American Fossil Mosses, with Description 

 of a New Species from Florissant, Colo.: 

 Elizabeth G. Britton and Dr. Arthur 

 HoLLicK, New York Botanical Garden. 

 During the summer of 1906 Professor 

 Theo. D. A. Cockerell and his wife made 

 extensive collections of fossil plants in the 

 well-known Tertiary beds at Florissant, 

 Colorado. From among the specimens col- 

 lected a beautifully preserved fossil moss, 

 in fruit, was kindly transmitted to us for 



examination. It will shortly be described 

 and published under the name Glyphomi- 

 trium Cockerellece. The specimen is here 

 for examination. 



Thousands of specimens of fossil plants 

 have been obtained from this locality by 

 other collectors from time to time, but only 

 three which have been regarded as mosses 

 have been heretofore brought to light, and 

 none of these is in fruit. 



This class of plants is exceedingly rare in 

 the fossil state and all of the hitherto de- 

 scribed American species are sterile, the 

 generic determinations having been based 

 entirely upon leaf characteristics, so that 

 such determinations were neither conclu- 

 sive nor satisfactory and in some instances 

 even their reference to the mosses is ques- 

 tionable. The specimen before us may 

 therefore be said to be the first one from 

 America in which a positive identification 

 has been possible. 



Some Changes in Wood Fiber immersed in 

 Water: Dr. H. von Schrenk, Missouri 

 Botanical Garden. 



Recent Identifications of Cretaceous Gym- 

 nosperms from Kreischerville, N. Y.: Dr. 

 Arthur Hollick, N. Y. Botanical Gar- 

 den, and Professor Edward C. Jeffrey, 

 Harvard University. 



One of the best founded adverse criti- 

 cisms in paleobotanical work is that deter- 

 minations of generic and family relation- 

 ships of fossil plants are necessarily based 

 almost exclusively upon external char- 

 acters. This has undoubtedly been the 

 case in regard to the determination of 

 fossil leaves, both of angiosperms and of 

 gymnosperms, and it will continue to be 

 inevitable as long as only the impressions 

 of the leaves are available for study. If, 

 however, certain of the leaves or leaf im- 

 pressions are found associated or actually 

 connected with twigs, or branches, or cones, 



