344 SUMMARY OF CURRENT RESEARCHES RELATING TO 



workers are needed. He desires especially that agriculturists should 

 everywhere take note of the existence of alternative hosts, such as the 

 Barberry, etc., and of their influence on the propagation of rusts. 



Taxonomic Importance of the Spermogonium.* — J. C. Arthur 

 disclaims any intention of deciding as to the true nature of the spermo- 

 gonium in Uredineae. He considers it a "problematical organ sui generis, 

 and that all the other rust spores are of a conidial or asexual character." 

 He traces the life-cycle of the Uredinea? as worked out by certain 

 writers, beginning with the teleutospore in which the fusion of the two 

 mycelial nuclei has taken place. The bi-nucleate character, he states, 

 is again established in the sporidium to continue through all the forms 

 onward to the teleutospore. Arthur describes the various spore forms 

 and notes that the spermogonium, which always appears at the beginning 

 of the life-cycle, never repeats itself. In reference to its taxonomic 

 value he insists that it should always be described by collectors, and the 

 spore-generation with which it is associated ; if, for instance, it is accom- 

 panied by uredospores, it can at once be concluded that there is no 

 fecidium in the life-cycle. Position, form, colour and size are also 

 characters worth recording, though of minor importance. They have 

 all more or less specific value and aid in identification. 



On the Origin of Parasitism in Fungi .f — George Massee claims 

 to have proved that parasitism in fungi is an acquired habit. Though 

 the spores of the parasite germinate on any moist surface, they do not 

 continue to grow unless on the particular species of plant of which they 

 are known to be the parasite. This selective power of the fungus is 

 due, Massee says, to chemotaxis ; and he made a large number of ex- 

 periments to find the substances that were favourable to the develop- 

 ment of the parasite. Fungi that are saprophytic can be induced to 

 penetrate the host-plant, by injecting into it a substance that is posi- 

 tively chemotactic to the germ tube of the fungus. He found that 

 infection took place more readily during the night when the cells were 

 more turgid, and more sugar and other chemotactic substances were 

 present in the cell-sap. 



New and Interesting Californian Fungi.J — Edwin Bingham Cope- 

 land describes new species of Coprinus, Battarrea and Podaxon, and 

 gives careful notes of some Californian Morels. A large number of 

 these were gathered, and he found that they all had transition forms 

 from one to the other. They fell into three groups referable to M. 

 conica, M. esculenta and M. hybrida. Copeland does not consider, 

 however, that these represent but one species. He agrees with European 

 mycologists that some parent type has given rise to several distinct lines 

 of descendants, and the differences are now constant. 



He gives notes on the function of Coprinus cystidia, which in C. 

 fuscosporus sp. n., certainly act as props and braces to hold the moist 

 gills apart and allow the spores to fall out. 



* Bull. Torr. Bot. Club., xxxi. (1904) pp. 113-25. 

 t I'roc. Roy. Soc, Ixxiii. (1904) pp. lhS-19. 

 X Ann. Mveol., ii. (1904) pp. 1-8(2 pis). 



