594 MUCEDINES. 



On wood-anemone. 



Extremely minute, at lengtli gray-brown j flocci simple, abbreviated, their 

 tips denticulate. 



1777. Peronospora gangliformis. i?t'r^. " Lettuce Peronospora." 



Threads of the mycelium stout, now and then torulose ; 

 suckers vesicular, obovate, or clavate ; fertile threads 2-6 times 

 dichotomous, sometimes trichotomous ; stems and primary 

 branches slender, dilated or inflated above ; the ultimate ramuli 

 inflated at the apex into a turbinate or subglobose vesicle bear- 

 ing from 2-8 subulate processes or spicules ; acrospores minute, 

 subglobose ; apices with broad, depressed papillae, produced on 

 the spicular processes. — Coohe Micr. F.t. 14,/. 265. Pop. Sc. 

 Rev. iii. t. 8.f. 4. Boti^ytis ganglioniformis. Berk. Journ. Hort. Soc. 

 i. t. 4. Ann. N.H. no. 526. Fckl. exs. no. 33. Cooke exs. no. 190. 

 Rahh. exs.no. Ill b^ F.E. no. 290. Bremia lactucce. Reg. Bot. 

 Zeit. 1843, t. 3. B. Botrytis geminata. Ung.Bot. Zeit. 1847, t. 6, 



/.9. 



On lettuce leaves. Spring. Common. 



1778. Peronospora parasitica. Pers. " Cabbage Peronospora." 



Threads of the mycelium thickened and much branched ; 

 suckers numerous, branched ; branches clavate, obtuse; fertile 

 threads thick, soft, flexile, equal, or unequal, 5-8 times dicho- 

 tomous, rarely trichotomous ; branches always repeatedly trifur- 

 cate ; acrospores broadly elliptical, very obtuse at the apex, 

 white. — Cooke Micr. Fung. t. 13,/. 262. Pop. Sc. Rev. iii. ^.8,/. 1. 

 Berk. exs. no. '^'^1. Botrytis parasitica. Fng. Fl.Y.p. S4i3. Pers. 

 Obs. i. t. 5,/ 5. Mucor botrytis. Sow. t. 359. Ayres. exs. no. 50. 

 Corda.Y.f. 18. Rabh. exs. no. 11 o and 324, F.E. no. 86. Fckl. 

 exs. no. 5. 8. 23. Cooke exs. no. 193. 



On cruciferous plants. Common. [Low. & Mid. Carolina.] 



1779. Peronospora viciae. Berk. " Pea Peronospora." 



Fertile threads densely csespitose, erect, equal, rarely unequal. 

 6-7-8 times dichotomous ; ultimate ramuli shortly subulate, 

 acute : acrospores ellipsoid, very obtuse at the aj)ex, obtuse or 

 slightly acute at the base ; membrane with a violaceous tint. — 

 Cooke Micr. F. 1. 15, / 266, t. 10,/ 212. Pop. Sc. Rev. iii. t. 8,/. 

 5. Botrytis vicice. Berk Journ. Hort. Soc. i. p. 31. B. 4'- Br. Ann. 

 N.H. no. 524. Rabh. exs. ii. no. 490. 



On leaves of peas and tares. Common. 



