814 



SCIENCE 



[N. S. Vol. XXX. No. 779 



sexual or resting spores. As reported in our 

 earlier paper,' oogouium-like bodies were 

 found almost immediately after the incep- 

 tion of this work, in cultures on raw potato, 

 lying in the mycelium close to the surface of 

 the substratum. Subsequently they were 

 found in greater abundance in potato gelatin 

 cultures, here imbedded in the culture 

 medium. Growth with varying degrees of 

 vigor has also been secured upon several 

 other synthetic media, including some modifi- 

 cations of the lima-bean agar, recommended 

 by Dr. G. P. Clinton. The oogonium-like 

 bodies have, however, been found but rarely 

 upon any medium except the potato gelatin 

 and the lima-bean agar. Under favorable cir- 

 cumstances they have been obtained in these 

 in sufficient abundance to permit much more 

 convincing study of the details of their de- 

 velopment than was reported in our former 

 paper. The most important advance, how- 

 ever, is the discovery of what appears to be 

 fully matured resting spores. The oogonium- 

 like bodies are about 30 microns in diameter, 

 hence distinctly larger than the regular 

 sporangia (conidia) and so different in ap- 

 pearance and mode of production as to pre- 

 clude the idea that they are closely related to 

 them. The character of the wall especially 

 differentiates these two reproductive bodies, 

 the oogonium-like bodies soon developing a 

 thicker wall, immediately in contact with cyto- 

 plasm, which may show stratification and 

 which in turn may be enveloped in an ex- 

 ternal envelope, of which the details as to 

 development and structure vary with the 

 medium in which they lie. No body clearly 

 comparable to an antheridium has as yet been 

 discovered. Nevertheless numerous examples 

 have recently been found where these oogon- 

 ' A paper dealing with this subject was read by 

 the present writer and N. J. Giddings before the 

 last meeting of the Botanical Society of America 

 and abstracted in Science (N. S., XXIX., 271). 

 The removal of Mr. Giddings to West Virginia has 

 left the responsibility for directing further study 

 with the writer, who is fortunate in now having 

 the assistance of Dr. B. F. Lutman and Mr. C. R. 

 Orton. Professor H. A. Edson has also assisted, 

 especially in devising culture media. 



ium-like bodies have apparently developed 

 into mature resting spores. These have a 

 thick spiny brown exospore with dense granu- 

 lar contents, bearing a general resemblance 

 to the oospores of related Peronosporales. 

 None have as yet been germinated hence it re- 

 mains to be proved whether they do actually 

 function as resting spores. We have found 

 similar bodies in potato leaves rotted by 

 PhytopMliora. There is need of further 

 painstaking work, including cytological 

 studies now being made by Dr. Lutman, be- 

 fore final conclusions are justifiable, but the 

 evidence at hand encourages the hope that we 

 have in hand the long sought for resting 

 spores of PhyiopMhora infestans. 



L. K. Jones 

 Botanical Laboratory, 

 University of Vermont, 

 October 15, 1909 



COLLECTION OF THE ^CIAL STAGE OF CALYPTOS- 

 PORA COLUMNAEIS (aLB. & SOHW.) KUHN 



The aecial stage of the blueberry rust, 

 Calypiospora columnaris (Alb. & Schw.) 

 Kiihn, was collected on Ahies halsamea near 

 Pictou, N. S., by the writer on July 14 of the 

 present year. 



Wintered telial material of this rust which 

 is abundant on the blueberry (Vaccinium 

 pennsylvanicum) , was sent to Dr. J. 0. 

 Arthur for his culture work. He found the 

 teliospores viable and on his suggestion search 

 was made in the vicinity of the collection for 

 the fecial stage. A Peridermium was found 

 on the leaves of Ahies halsamea, which agreed 

 with the description of Peridermium colum- 

 nare. Part of the collection was forwarded 

 to Dr. Arthur, who determined it as the secial 

 stage of Calypiospora columnaris, and this as 

 the first collection in North America. 



This Peridermium, which could be easily 

 recognized in the field by its yellow color, due 

 to the orange-colored spores, was found spar- 

 ingly distributed over an area of several square 

 miles on the young leaves of the lower branches 

 of its host. Ill no case was it abundant, only 

 a few leaves being affected. In several places 

 the leaves of young trees a few inches from the 

 ground showed a more pronounced infection. 



