PHYSIOLOGY AND MORPHOLOGY OF CALIFORNIA HEPATIC^ 1 5 



resemble the sclerotia formed in the cells of Fosso')nhronia^ 

 though they do not develop in such great numbers. This is 

 doubtless due to the fact that the comparatively early decline 

 and death of the host tissues impairs the vigor and health 

 of the parasite before these structures can develop in great 

 numbers. 



As soon as the host cells begin to show the effects of para- 

 sitism there develop upon the surface of the host at indefinite 

 points along the surface-hyphas, perithecia-like structures (Fig. 

 11) the real function of which, however, has not been demon- 

 strated. Professor Roland Thaxter kindly attempted to iden- 

 tify the fungus for me but being unable to determine the true 

 nature of these structures was forced to wait for more advanced 

 stages. The writer has prepared a number of slides of micro- 

 tome sections which show these bodies to be hollow. 



Beyond a wall no other structures have yet been observed in 

 connection with the interior of these somewhat globular bodies. 

 They seem to develop from short processes that appear here and 

 there along the external hyphee. They assume very early the 

 spherical habit and develop at various points on their surface 

 short spine-like processes at first pointing in different directions 

 but ultimately either disappearing or lying all in one plane at 

 the base of the structure bearing them. On certain host plants 

 the tissues of which have already begun to turn brown, these 

 perithecia-like bodies develop in such numbers as to be almost 

 in contact, and the complex of hypha^ on the surface and within 

 the host is very elaborate. Two-celled conidia were found on 

 the surface of the host but it could not be proved that these 

 spores belonged to the fungus infecting Aneura, although no 

 other fungus was observed in the material. 



It is the intention of the writer to work out the development 

 and life history of this fungus and the one associated with I^os- 

 sonibronia more fully in a later paper. At the present moment 

 the main object is to discuss the relation of parasite and host. 

 In the case of this fungus there is less evidence of anything 

 comparable to a symbiotic relation than in the relation of the 

 Fossoinbro7iia parasite to its host. In fact, as soon as infection 

 is brought about, the host seems to show signs of resulting 



