Classification, 119 



Peronospora parasitica, De Bary (figs. 45, 46, 129). 



Mycelium thick, very much branched, branches 

 thick, obtuse or subclavate, curved, often entering 

 into and filling up the cells of the host, haustoria 

 numerous, branched ; gonidiophores thick, soft, 

 flexuous, equal or unequal, 5 — 8 times dichotomously, 

 rarely trichotomously divided, branches repeatedly bi-, 

 trichotomous, the branches continue to become more 

 slender from the first order, ultimate branchlets 

 subulate, more or less arcuate ; gonidia broadly 

 elliptical, colourless, apex very obtuse, 20-25x16- 

 20 fi ; oogonia angularly globose, membrane very 

 thick, stratified colourless or yellowish, oospores 

 globose, smooth or slightly rugulose, yellowish or 

 brownish, 25-45 fi diameter. 



Peronospora parasitica, De Bary, Ann. Sci. Nat. 

 ser. iv. vol. xx. p. 110; Sacc. Syll. vii. 830; Cke. 

 Hdbk. n. 1778; Cke. Micr. Fung. t. 14, f. 265. 



On leaves and inflorescence of various cruciferous 

 plants, often in company with Cystopus candidus. 

 Has been met with on various species of the following 

 genera — Gapsella, Nasturtium, Barharea, Turritis, 

 Arahis, Cardamine, Dentaria, Hesperis, Sisymbrium, 

 Erysimum, Cheiranthus, Matthiola, Brassica, Sinapis, 

 Alyssium, Eriophila, Camelina, Thlaspi, Lepidium, 

 Diplotaxis, Bunias, Raplianus, Neslia. Not un- 

 common, 



Peronospora ficarise, Tul. 



Forming broadly effused, dirty white, then greyish- 

 lilac tufts ; gonidiophores short, 5 — 7 times equally or 

 unequally dichotomously ^divided^ ultimate or penulti- 



