340 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The Genus Phragmidium.* — P. Dietel has been occupied in 

 determining the distribution and identity of species of Phragmidium^ 

 especially of those recorded from America. Only three forms have been 

 found in the Southern Hemisphere ; 25 forms are reported from 

 America. Dietel describes these, and adds four to the North American 

 flora. He notes many peculiarities of distribution, as, for instance, the 

 Australian Ph. Bamardi, which grows on Rubus parvifolius, and of 

 which the spores germinate at once on the same host. This same type 

 of fungus has been found in Japan, also on Rabus parvifolius, and 

 differing only in the number of cells. Dietel considers it to be a variety 

 of the same species. He discusses the probable methods of transport of 

 the spores. Many American forms supposed to be identical with those 

 of Europe, have been found, on more careful examination, to be distinct 

 species. 



Notes on Uredinese.f — Luigi Mentemartini found the Oncidium 

 plants in Padua attacked by a Uredo ; he watched its growth for a year, 

 but only uredospores were produced. The sori occupied both sides of 

 the leaf. He noted that the plant-cells immediately adjoining the 

 fungus retained their green colour longer than the rest of the leaf. The 

 new species is called Uredo aurantiaca. 



M. A. CarletonJ has investigated the rusts of a number of plants in 

 order to arrive at more definite knowledge of their life-histories. Uro- 

 myces Euphorbia produced all the different stages on the one host-plant. 

 Puecinia Helianthi is peculiar to some of the species of the genus 

 Helianthus ; the iEcidium is of rare occurrence, the Uredo form often 

 growing from a teleutosporic infection. The crown rust of oats was 

 found to form its iEcidiuin ! on Rhamnus lanceolata. Among other 

 results he notes that it is possible for a perennial rust to exist in an 

 annual host, the mycelium being carried over in the seed of the plant. 

 " Such an instance is practically certain in the Euphorbia rust." 



W. Tranzschel § has established several new cases of hetercecism in 

 rusts. JEcidium Trientalis, he finds, is identical with Puecinia Karelica,. 

 on Carex; JEeidium coruscans with Chrysomyxa Ledi, the teleutospores 

 inducing a witch's broom on Ledum. He has also identified Ochrospora 

 fiorbi with JEcidium leucospermum. 



In another paper jj he points out how the morphological form may 

 aid in determining the biological relationship. Thus he finds that the 

 teleutospores of Puecinia Amphibii agree exactly with those of Puecinia. 

 Morthieri, which inhabits Geranium silvaticum. He therefore looks for 

 its iEcidiurn on the G. silvaticum, and finds JEcidium sanguinolentum 

 the related form. The teleutospores of Uromyces Rumicis and those of 

 Uromyces Eicariee are identical, and he finds the iEcidiuni of the forms 

 also on Ranunculus Ficaria. Several other similar instances are given 

 of this rule of identity. 



* Hedwigia, xliv. (1905) pp. 112-32 (1 pi.). 

 t Atti Ist.Bot. Pavia. viii. (1904) pp. 99-101 (1 pi.). 

 t U.S. Dept. Agric, Bull. 63 (1904) 29 pp. (2 pis.). 



^ Travaux du Muse'e bot. Acad. Imp. Sci. St. Petersburg, ii. (1904) 17 pp. 

 II Arb. K. St. Petersburg Natur. Geaell., xxxv. (1904) 13 pp. See also Bot. Zeit.„ 

 lxiii. (1905) pp. 75-6. 



