Nov. is, 1920 Crownwart of Alfalfa Caused by Urophlyctis alfalfae 301 



Provisionally, it appears advisable to follow Magnus in recognizing 

 the alfalfa parasite as a distinct species, not, perhaps, so much on 

 account of some differences in morbid host anatomy as because of the 

 general improbability that two unrelated plants serve as hosts to a 

 parasite which shows in general no omnivorous tendencies. The beet 

 disease has not been reported in the regions where crownwart is preva- 

 lent; and Chenopodium spp. with every chance for infection have not 

 been observed to be attacked. Reference has been made in another 

 connection to Spegazzini's (32) report of crownwart on Medicago denti- 

 culata and its absence from alfalfa in the same range. This condition 

 could most readily be attributed to the existence of another species 

 producing similar galls. 



DEVELOPMENT AND MORPHOLOGY OF THE FUNGUS 



The morphology of the crownwart organism has not hitherto received 

 much attention. Magnus (20) made some observations regarding en- 

 larged hyphae frequently found in old material and referred to the pres- 

 ence of a hyaline cell attached to the concave side of the resting spores; 

 but in the main his specific details concern the pathological anatomy of 

 the host. In more recent years, Wilson (37) published a cytological 

 account of Urophlyctis alfalfae, arriving at conclusions considerably at 

 variance with those of Magnus. The utilization of old material by both 

 these writers may largely account for their failure to observe important 

 details of development and morphology, as well as explain interpre- 

 tations that it appears impossible to reconcile with conditions as found 

 in young material much more favorable for study. 



GERMINATION OF THE RESTING SPORES 



As has long been recognized, the fungus passes through the prolonged 

 periods of summer drouth by means of the resting spores contained 

 within cavities in the galls of the host. In the course of the rainy season 

 the galls disintegrate completely, thus setting free the spores; and it is 

 not improbable that the exposure incident to this method of liberation 

 may be necessary for germination. However, the conditions that may 

 favor germination remain more or less obscure; for although many at- 

 tempts were made by the writers with spores from freshly gathered 

 material both old and young, as well as with limited supplies of material 

 that may, in addition, have suffered deterioration in transit, the results 

 obtained have been so meager and dubious that this phase of the life 

 history of the fungus must be reserved for a later paper. In a number of 

 preparations an appearance was noted as of resting spores producing a 

 number of subspherical bodies varying from 1 to 9, by the passage of 

 protoplasm through pores in the spore wall. The vesicles that usually 

 attained half the linear dimensions of the spore in some cases were seen 



