10 
unusually favorable conditions for the preservation of very deli- 
cate structures, such as insects, petals of flowers and similar 
structures which are entirely destroyed under ordinary conditions 
of sedimentation. A number of specimens collected in this 
locality by Professor Cockerell have been submitted to the Garden 
for critical study. From the material already examined, three 
new species have been described and the types preserved in the 
museum of this institution. Of these, one specimen of moss 
represents the first record, for America, of a fossil moss in fruit. 
Mention was also made of fossil plants collected in connection 
with mammoth remains at Elephant Point, Alaska, received from 
the American Museum of Natural History. Among these are 
several specimens of mosses identical with living species occurring 
in northern regions. Specimens of wood from a fossil beaver dam 
at this place were also shown. 
Mr. B. C. Gruenberg spoke of some of the problems connected 
with the study of mycorhiza, delicate fungous threads associated 
with the roots of many of the higher plants. The existence of 
such structures has long been known and many theories have been 
advanced to explain their origin and the relation existing between 
them and the host on which they occur. The most commonly 
accepted view at the present time is that of the symbiotic or 
mutual relationship existing between the two organisms. The 
fungous filaments are thought to be beneficial to the host in 
several ways, such as the disintegration of soils and absorption 
of water, thus functioning as root hairs, these benefits being ren- 
dered in return for those offered by the host to the parasite. 
It has been thought that plants in which mycorhiza are normally 
present cannot live without them but this has been proved to be 
untrue in case of plants with the green coloring matter, chloro- 
phyl. Mr. Gruenberg is making a special study of mycorhiza-in 
certain of the orchids. 
Miss Mary P. Anderson read a very interesting paper on the 
organization of nature study in the public schools, which paper 
will be published entire in a later number of the Journa Dis- 
cussions followed the reading of each of these papers ee much 
interest was shown by those present. 
F. J. Seaver. 
