PHYCOMYCETES 357 



(J3ot.}, vol. x. p. 363 (1869). Forming very delicate white 

 patches on the under surface of the leaf; conidiophores 

 repeatedly dichotomously branched, branches spreading, 

 ultimate branchlets acute, straight, spreading; conidia 

 hyaline, elliptical, 25-32 X 18-20 /*. 



Peronospora hyoscyami, De Bary, Ann. Set. Nat., ser. iv. 

 vol. xx. p. 123. Forming dirty greyish-violet tufts of the 

 under surface of the leaf, sometimes small, at others 

 effused over the greater portion of the surface; conidio- 

 phores 300-500 fj. high, averaging 300 n, 5-8 times 

 dichotomously branched near the apex, branches spread- 

 ing, ultimate ones very divergent, short, awl shaped; 

 conidia small, elliptical, ends obtuse, pale dingy violet, 

 15-24X13-18^; oospore unknown. 



Peronospora maydis, Raciborski, Ber. Deutschen Bot. 

 Gesell., xv. p. 475, 4 figs. (1897). Conidia emerging 

 through the stomata, 0-3 mm. high, and up to 25 p. thick, 

 with 1-3 main dichotomous branches, which are divided 

 at the tip into 3-6 conical, pointed branchlets, each bearing 

 a smooth, hyaline, globose conidium 15-18 /u, diam. ; 

 oospores globose, membrane smooth, 14-24 p diam. 



ASCOMYCETES 



Spores produced in large mother-cells or asci ; asci 

 either naked, or more frequently produced within an 

 excipulum, or a perithecium ; perithecium either with a 

 distinct opening through which the asci escape at maturity, 

 or rupturing in an irregular manner, but never exposing 

 the disc or hymenium ; excipulum expanding and exposing 

 the hymenium at maturity. 



Gvmnoasaceae. Perithecium and excipulum absent, 



