The Scottish Naturalist. 81 



old Aberdeen. There were no signs of conidia on the 

 surface of the plants. 



9. P. Arenariae Berk. 5, 8. on 



Arenaria trinervia and A. peploides. 

 Sub-sect. b. Leiothecce. Oospores smooth, or with a few 

 low ridges only. 



10. P. parasitica (Pers.) Tul. 1, 2, 3, 4, 5, 7, 8, 10. Abundant 



(often causing galled conditions of the flower-stalks and 



flowers) on 

 Cheiranthus Cheiri. 

 Sisymbrium officinale and 8. Alliaria. 

 Brassica oleracea, B. Rapa, B. Sinapistrum. 

 Capsella Bursa-pastoris. 

 Raphanus Raphanistrum. This species is very often found 



on the same plants as, and often accompanying, 



Cystopus candidus. 



11. P. FicariaB Tul. 5, 7, 8. Common, and often associated 



with Entyloma Ficarice, in 

 Ranunculus Ficaria and R. repens. In the latter host, this 

 association with Entyloma has not been observed. 



12. P. arborescens Berk. (Scot. Nat, 1883, p. 34). 5, 7, S. on 

 Papaver dubium. Only conidia observed. 



P. Argemone. Oospores found at Lunan, near Montrose, 

 in June, 1885. 



13. P. affinis Rossm. (Scot. Nat., 1883, p. 85). 7, 8. Local, on 



Fumaria officinalis, near Forres, and 

 F. densiflora, near Aberdeen. 



14. P. obovata Bon. 7, 8. on 



Spergula arvensis, with conidia only, near Aberdeen ; and 

 with oospores (in plants that mostly showed no conidia) 

 at Gamrie, in Banffshire. Not previously recorded as 

 British. 



15. P. TrifoliCTUm De Bary. 5, 7. In some places common. On 



Medicago lupulina, at Lunan, near Montrose. 



Trifolium pratense, near Aberdeen. 



T. medium, Muchalls. 



Lotus corniculatus, Glamis (J. S.) 



16. P. PotentillSB De Bary (Scot. Nat., 1884, p. 276). Scarce on 



AlchemiUa vulgaris, 8, Rothiemurchus. 

 Var. Gei, Trail, on Gev.m rivale, 7, near Aberdeen. 



F 



