12G 



PHYCOMYCETES. 



swarm-spores which escape from the enclosing coats and germinate 



on seedling plants. 



De JBary J found germ-tubes of 

 Gystopus entering all the stomata of 

 Lepidium sutirum and of Capsclln, 

 but they only developed further if 

 the part attacked were the cotyledons. 



Magnus 2 observed an infection of 

 Raphanus Raphanistrum in which the 

 unopened buds were infected by swarm- 

 spores. Oogonia may be found in the 

 flowers of this same plant, whereas 

 conidia alone only are present in 

 Capsella. 



White rust is most commonly 

 observed on C'.qwH", causing slight 

 local swelling or marked hypertrophy. 

 It is also found to injure radish 

 (Rl>]i<ini(_s sativus), horse radish 

 (Cochlearia armoracia), cress (Lepidium 

 xt(tivum), species of cabbage and 

 turnip (Bmssica Napus, B. niyra, B. 

 Jtapa, B. olcracea), wall- flower (Cheir- 

 antkus Cheiri), water cress (Nasturtium 

 amphibium, etc.), caper-plant (Capparis 

 spinosd), and other wild and culti- 

 vated plants belonging to, or closely 

 allied to the Cruciferae. 



Wakker 3 investigated the changes 

 brought about on a number of Cruci- 

 ferae by Cyst <>pus. Some plants showed 

 little or no deformation or anatomical 

 alteration, others showed much. While 

 FIG. -AT. Cystopus portuiacae, D. c. the anatomical changes in the various 



'in. mycelium ; f, basidia ; c, spores . . -. , 



with intermediate ceiis. (After species examined agreed in general, 



Tulasne.) i j -, 



yet some showed a predominant or 

 exclusive formation of conidia, others of oospores. 



The changes 



1 Morphology and Bioloyy of the Funyi. English Edition. 

 - Abhand. d. lotan. Verem* d. Prov. Brandenburg, xxxv. 

 3 Prinysheirn' s Jahrbuch, 1892. 



