=Peronospora gangliformis=, Berk. LETTUCE MOULD; 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 bearing from 2-8 subulate processes or spicules; acrospores minute, subglobose; apices with broad depressed papillæ, produced on the spicular processes, On Lettuces and other _Compositæ_. Frequent. (Plate XIV. fig. 265.) =Peronospora parasitica=, Pers. CABBAGE MOULD; 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 dichotomous, rarely trichotomous; branches always repeatedly trifurcate; acrospores broadly elliptical, very obtuse at the apex, white.—On Cabbages, Shepherd’s-purse, and other Cruciferæ, sometimes in company with _Cystopus candidus_. Summer and autumn. Common. (Plate XIII. fig. 262.) =Peronospora Viciæ=, Berk. PEA MOULD; fertile threads densely cæspitose, erect, equal, rarely unequal, 6-7-8 times dichotomous; ultimate ramuli shortly subulate, acute; acrospores ellipsoid, very obtuse at the apex, obtuse or slightly acute at the base; membrane with a violaceous tint.—On Tares, Peas, &c. Frequent. (Plate XV. fig. 266; Plate X. fig. 212.) =Peronospora Arenariæ=, Berk. SANDWORT MOULD; fertile threads slender, 6-7 times equally, rarely unequally, dichotomous; branches spreading; ultimate ramuli slender, acute, subulate, nearly erect; acrospores broadly elliptical, oftentimes very obtuse, small; membrane scarcely violaceous.—On _Arenaria serpyllifolia_ and _A. trinervis_.—June. (Plate XVI. fig. 268; Plate X. fig. 211.) =Peronospora effusa=, Grev. SPINACH MOULD; fertile threads fasciculate, short, thick, 2-6, rarely 7 times dichotomous above; acrospores broadly ellipsoid, sometimes very obtuse; membrane with a violaceous tint. On Spinach, Goosefoot, and some other allied plants. Spring and autumn. Not uncommon. (Plate X. figs. 214, 215.) =Peronospora Urticæ=, Casp. NETTLE MOULD; fertile threads small, loosely 4-6 times dichotomous; branches flexuose, ultimate ramuli subulate, arcuate, often deflexed; acrospores large, broadly ovoid or subglobose, distinctly pedicellate; apices very obtuse; membrane violaceous.—On leaves of the common Nettle. =Peronospora trifoliorum=, De By. CLOVER MOULD; fertile threads cæspitose, equally or unequally 6-7 times dichotomous, rarely trichotomous; ultimate branches subulate, acute, slightly curved; acrospores ellipsoid, very obtuse; membrane with a slightly violaceous tint; oospores large; epispore brown.—On Lucern (_Medicago sativa_). Highgate and Hampstead, 1864.