PERENNIAL MYCELIUM OF PARASITIC FUNGI. 

 L. H. PAMMEL.* 



Ill an interesting- and valuable article on the perennial my- 

 celium of some of tHie species of Peronosporea? Dr. I. E. IMelhus' 

 calls attention to tire perennial mycelium of the following species : 

 PhijtophtJwra infestans, Phytopkthora cactoriun, Cystopus 

 cmididus, Plusmopar^a viticola, Plasmopara pygmaea, F'lasmopara 

 hcdstedii, Peronospora dipsaci, Peronospora schachtii, Perono- 

 spora alsinearmn, Peronospora grisea, Peronospora effusa, Per- 

 onospora ficariae, Peronospora parasitica, Peronospora viciae, 

 Peronospora rumicis. In a review of this paper by the writer, 

 attention was called to tlie perennial character of Plosmopara 

 viticola' in our Vitis vulpma.- 



I hiave observed water sprouts on Vitis vnlpina, not only in 

 Iowa, but in La Crosse, Wisconsin, and Sandusky, Ohio, which, 

 in some cases, were five feet long and completely covered with 

 the conidiophores and spores of the fungus. This state of affairs 

 on the Yitis v'idpina> is a very com:mo'n occurrence. Infected 

 water sprouts are not so common in Iowa, but the percentage 

 of infection is rather large when compared with plants under 

 other conditions. Probably many other species of the family 

 have a perennial mycelium. These will no dombt be l>rought 

 to light in a study of this interesting group of fungi. It is to 

 be hoped that Dr. Melhus will continue his investigations. I 

 might mention in this connection that the mycelium of the 

 Peronospora obducens on Impatiens fulva in "Wisco-nsin com- 

 monly occurs in the cotyledons of the plant. The Sclerospora 

 graminicola, so common at times on Setaria viridis and 8. itaJica 

 and 8. germmiica, is undoiibtedly seed borne. ^ Clinton"' has 

 shown that infected lima beans readily transmit the downy 

 mildew of the lima bean {PJiytophthora phascoli Thaxter.) In 

 a recent excellent paper by George A. Osner of Cornell I^ni- 

 versity,^ attention is called to the manner of infection of timothy 

 smut. Ustilago striaeformis (West) (Niessl) a fungus well 

 named because of the characteristic lead colored sori distributed 



ijour. Agrl. Research, 5, 67. 



=Rep. Iowa State Hort. Soc. .70, 151, 191.5. 



*From time to time the writer has made a few notes on parasitic fungi. 

 .Since the subject of fungi is not especially engaging his attention just now, 

 it seemed best that these notes should be brought together. 



^Bull. Iowa Agrl. Exp. Sta., 104, 241. L. H. Pammel, J. B. Weems and F. 

 Lamson-Scribner. Bull. Iowa Geol. Survey 1, 88 : This paper gives the earlier 

 references to Farlow, "Webber, Halsted and Trelease. 



^Rep. Conn. Agrl. Exp. Sta.. 1905, 278-303. pi. M-2i. 



■'Bull. Cornell Univ. Agrl. Exp. fcta. 381, 189-230, pi. J7 f. JiS-nS. 



