12G 



rHYCOMY(JKTE.S. 



swarm-spores which escape from the enclosin<^ coats and germinate 

 on seedling ])lants. 



De Bary ^ found germ-tubes of 

 Cystopus entering all the stomata of 

 Lcpidium sativum and of Ccq^sella, 

 but they only developed further if 

 the part attacked were the cotyledons. 



Magnus '^ observed an infection of 

 Raphanus Raphanidrum in which the 

 unopened buds were infected by swarm- 

 spores. Oogonia may be found in the 

 Howers of this same plant, whereas 

 conidia alone only are present in 

 CapiicU((. 



White rust is most cbnnnonly 

 observed on Capsella, causing slight 

 local swelling or marked hypertrophy. 

 It is also found to injure radish 

 {Raphanus sativus), horse radish 

 {Coehlcaria armoracia), cress {Lcpidium 

 mtimim), species of cabbage and 

 turnip (Brassica Nap)us, B. nigra, B. 

 Rap)a, B. oleracea), wall- flower (Cheir- 

 anthus Cheiri), water cress {Nasturtium 

 amphibium, etc.), caper-plant {Gapparis 

 spinosa), and other wild and culti- 

 vated plants belonging to, or closely 

 allied to the Cruciferae. 



Wakker^ investigated the changes 

 l)rought about on a number of Cruci- 

 ferae by Oi/sfajms. Some plants showed 

 little or no deformation or anatomical 

 alteration, others showed much. While 

 the anatomical changes in the various 

 species examined agreed in general, 

 yet. some showed a predominant or 

 exclusive formation of conidia, others of oospores. The changes 



Fig. '.iT.—Cystopus poriiUacac, D. C. 

 m, mycelium ; ./', basidia ; c, spores 

 with intermediate cells. (After 

 Tiilasiie.) 



' Morpholo<iy and Biolo(jy of tht Fuwji. Englisli Edition. 

 - Abhand. d. hotan. Vereinn d. Proi\ Brandenhunj, xxxv. 

 ^ Pringsheim's Jahrbuch, 1892. 



