124 British Ftmgi, 



Pe^'onospora effusa, Rabenh. 



Forming effused greyisli spots ; gonidiopliores fasci- 

 culate, emerging througli the stomata, short, thick, 

 2 — 7 times dichotomously divided above, ultimate 

 branchlets thick, shortly subulate, curved downwards ; 

 gonidia elliptical, distinctly pedicellate, pale dingy 

 lilac, 25-35 x 15-24 /x ; oospore globose, epispore 

 clear brown, irregularly wrinkled, 25-38 /jl diameter. 



Peronospora effiiscij Herb. Myc. Fung. no. 1880; 

 Sacc. Syll. vii. n. 854; Cke. Hdbk. n. 1781; Cke. 

 Micr. Fung. t. 10, figs. 214, 215. 



On living leaves of plants belonging to the orders 

 Clienopodiaceoe, Polygonacese, and Violaceoe, as Cheno- 

 f odium album, C. muralisj C. glaucum, C. polysper- 

 nuim, C. liyhridum, C. Bonus-Henricus, Spinacia 

 oleracea, Atriplex patula, A. nitens, A. Imstata, A. 

 rosea, Polygonum convolvulus. 



The following varieties have not yet been met with 

 in Britain. 



Var. a minor, branches slenderer than in type, 

 erecto-patent, ultimate branchlets subulate, sub- 

 squarrose, straight or slightly curved, not deflexed ; 

 gonidia globoso-elliptical, pedicel scarcely conspicuous. 

 On Atriplex. 



Yar. ^ violce on leaves of VloIoj tricolor, var. arvensis. 



Yar. 7 polygoni, distinguished from the type form 

 by the whitish colour of the small tufts. 



Forming usually broadly effused patches on the 

 under surface of leaves. Common on cultivated 

 spinach. 



Peronospora urticse, De Bary. 

 Gonidiophores small, loosely 4-6 times dichoto- 



