28 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 
The Peronosporese of North Ayrshire. By D. A. Boyp. 
[Read 24th April, 1894.] 
Durine the last four seasons, I have attempted to ascertain the 
number of species of Peronosporex occurring in the North-western 
district of Ayrshire. with the host-plants on which they are 
parasitic. My observations have been made chiefly in the parish 
of West Kilbride, but I have also been able to include a few 
localities for species found in the adjacent parishes of Largs, 
Ardrossan, &c. Owing to the small area examined, it is probable 
that the list of 21 species is by no means exhaustive. 
The investigation of these parasitic microfungi has hitherto been 
much neglected in the West of Scotland, and little is known 
regarding their local distribution. The following list, although 
admittedly incomplete, is submitted in the hope that it may lead 
to further research. 
Genus Cystopus, Levéillé. 
1. Cystopus candidus (Pers.) Lév.—On Capsella Bursa- 
pastoris ; very common; Largs and West Kilbride. On Carda- 
mine hirsuta ; frequent; Seamill. On C. pratensis ; not common ; 
Chapelton. On Sisymbriwm officinale ; frequent; Noddsdale, 
Yonderfield, &e. On Brassica oleracea ; frequent; Seamills On 
Arabis alpina ; Seamill. 
2. C. spinulosus, De Bary.—Locally common on Cnicus 
palustris, and less frequently on C. lanceolatus; Kilbride and 
Kirkland Glens. 
Genus Phytophthora, De Bary. 
3. Phytophthora infestans (Mont.).—Very common on 
Solanum tuberosum, producing the well-known “ potato-disease ” ; 
Largs, West Kilbride, Ardrossan, &c, 
