176 Eumycetes. — Pflanzenkrankheiten. 



Olive, E. W., Origin of heteroecism in the rusts. (Phyto- 

 pathology. I. p. 139—149. Oct. 1911.) 



A general discussion of the problem as to which of the hosts 

 is to be regarded as primary and which secondary. It is held that 

 in the origin of heteroecious conditions, the host which bore the 

 hypothetical autoecious ancestor was the present gametophytic host. 

 This conclusion is based on several facts and cytological considera- 

 tions. First, since the uninucleate gametophyte is undoubtedly the 

 more primitive condition of the fungus, it follows that the primary 

 host of the autoecious ancestor was quite likely the present host of 

 this gametophyte and the present sporophytic host was secondary. 

 The stage of the sexual fusions marks the origin of the binucleate 

 sporophyte; and it is argued that this stage has equal morphological 

 value with the teleutospores. The only two necessary stages, in 

 fact, in the ontogeny of the rusts are those of the sexual fusions 

 and teleutospore formation. All other structures of the rusts are 

 regarded as secondarily acquired. 



Second, it is held that the Stimulus imparted by the sexual 

 fusions, being of the nature of the Stimulation of an egg, is the 

 most profound and the most invigorating of the whole life history. 

 It therefore follows that the diploid aecidiospores, which are produced 

 shortly following these fusions, are endowed with more vigor than 

 any of the rest of forms of rust spores; and are thus the most 

 capable of infecting foreign protoplasm. We may therefore argue 

 that, in the origin of heteroecism, the original jump to secondary 

 hostplants must have been performed by the vigorous aecidiospores, 

 and not by the uninucleate basidiospores. The possibility of bridging 

 by means of aecidiospores argues further for their vigor. 



Finally, the prevalence of heteroecious forms with pleophagous 

 sporophytes is regarded as a strong argument in favor of the theory 

 that the pleophagous habit arose directly from the invigorating 

 influence of the sexual fusions. The fewness and evident close rela- 

 tionship of the gametophytic hosts in each of these cases, as well 

 as the multiplicity and remote relationship of the sporophytic hosts 

 argues that the present gametophytic hosts were the primary hosts 

 of the hypothetical autoecious ancestor. Moore. 



Whetzel, H. H. and D. Reddick. A method ofdeveloping 

 Claviceps. (Phytopathology. I. p. 50—52. pl. 11. Ap. 1911.) 



Sclerotia collected in August were put out of doors until the 

 following April, when they were brought into the laboratory and 

 placed on moist sand at room temperature. The first signs of develop- 

 ment were in 12 days but some sclerotia required six weeks. Notes 

 made from day to day on the development are given. Moore. 



Bordas. Sur l'appareil sericigene des Chenilles de Phtho- 

 rimaea operculella. (C. R. Ac. Sc. Paris. CLIV. p. 618 — 620. 26 

 fevr. 1912.) 



La chenille de la teigne des Pommes de terre presente des 

 particularites anatomiques inconnues chez les autres Lepidopteres. 



P. Vuillemin. 



