608 SUMMARY OF OUERENT RESEARCHES RELATING TO 



conidial colour-substance in peculiarly formed mycelial hyphae, and the 

 formation of yeast-cells which increase by building. So far the author 

 had been unable to get the culture back to the normal plant, though 

 the most varied culture media were used. The yeast form had fermen- 

 tation power, a new development for Aspergillus. 



Penicillium avellaneum sp. n.* — Ch. Thorn and G. W. Turesson 

 found in cultures of this species that the ascus-producing form was 

 common ; it appeared in almost all of the media used. The cultures 

 tended to become more or less Indian-red. The small conidia were borne 

 on apical verticils with sterigmata. The perithecia had a peridium of 

 thick-walled cells. The ascospores have thick walls, pitted, or with the 

 appearance of round transparent spots. 



American Rusts. — C. A. Ludwigf has been studying the Cseoma 

 forms of rusts, and he now f gives a synoptic key with notes on Coleo- 

 sporium and Melampsora. In it he uses the wall of the uredinospore as 

 a distinctive character ; he finds that these walls are thickened in various 

 ways, and in some species are verrucose. The teleutospores are not of 

 much use in determining species. In Melampsora he makes use. of the 

 position of the pyenidia. Careful descriptions of some little-known 

 species follow. 



J. R. Weir % describes for the first time the teleutospore stage of 

 Gymnosporangium tubulatum. It forms lobed galls on the branches 

 and twigs of Juniperus scopulorum. The identification was suggested 

 by the association in place of Juniperus with Crataegus Douglasii, of 

 which the leaves were being destroyed by an aecidium. Culture experi- 

 ments have proved the relation between the two forms. 



Notes are also published of experiments on Peridermium pyriforme 

 by J. E. Kirkwood, § and they have gone far to prove that Pinus 

 ponderosa and Comamlru pallida are the alternate hosts of that fungus. 

 The fungus reacts on the tissues of both hosts in a similar manner, 

 ramifying through the resin ducts and intercellular spaces of the cortex, 

 traversing the medullary rays to the pit, and extending up and down 

 through the tracheids. The author does not claim to have definitely 

 settled the point, as galls have not yet been produced on the inoculated 

 host. 



Uredinese of Porto Rico.||— J. C. Arthur has described a series of 

 species in continuation of a previous paper. The genera Uromyces, 

 Puccinia, Pucciniosira and the form genus JEcidium are all represented 

 in this contribution. Pucciniosira is distinguished by the ascidioid 

 peridium of the sori and by the intercalary cells in the catenulate 

 teleutospores. Various descriptive and historical notes are given with 

 each species. 



* Mycologia, vii. (1915) pp. 284-7 (3 figs.), 

 t Phvtopath., v. (1915) pp. 273-81. 

 % Phytopath., v. (1915) p. 218. 

 § Phytopath., v. (1915) pp. 223-4. 

 || Mycologia, vii. (1915) pp. 227-53. 



