274 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



alternative host Amelanchier canadensis, brings about reversion to the 

 juvenile form of foliage when it attacks Juniperus virginiana. 



Cherry .—Sclerotinia fructigena ( = Monilia fructigena) is reported 

 killing shoots of Morello and other cherries, and S. seaveri {—-Oidium 

 destruens and (?) Monilia Linhartiana) those of the black cherry 

 {Prunus serotina). Witches' brooms, due to Exoascus cerasi, occur 

 occasionally, but rarely spread. The mildew, Podosphaera oxy- 

 acanthae, is destructive to cherries, but the Mahaleb and * Governor 

 Wood,' appear to be immune. Cylindrosponuin padi attacks green 

 fruits of Prunus virginiana as well as leaves, and is similar to the 

 disease prevalent in Europe on Prunus Padus, ascribed to 0. Tuheufi- 

 anum. 



Chestnut. — A canker due to the wound parasite, Valsonectria para- 

 sitica, on sweet chestnut occurred at Hicksville. 



Coreopsis tinctoria was attacked by Erysiphe cichoracearum , as was 

 Cosmos hipinnatus. The latter plant is also frequently attacked by 

 Phomopsis Stewartii, producing stem blight in mature plants. The 

 appearance of the disease is described and a technical description of 

 the fungus given. Inoculation experiments rarely succeeded. 



Pemphigius populicaulis and P. populi-transversus, forming galls 

 on petioles of Populus deltoides, are recorded. 



Cucumber is reported attacked by Erysiphe cichoracearum, as is 

 Dahlia. 



Hepatica. — A destructive parasite, Plasmopara pygmaea, was 

 apparently kept in check by Bordeaux mixture; it is thought that 

 the fungus is perpetuated both by perennial mycelium and by 

 oospores. 



Hollyhock.' — The association of Septoria parasitica Fautrey, and 

 Ascochyta parasitica with Puccinia malvacearum is noted. 



Honeysuckle. — Microsphaera alni var. lonicerae is reported on 

 Lonicera tatarica for the first 'time in America, the yellow-fruited plant 

 being apparently more susceptible than the red. 



Hop. — Leaf spot, Cylindrosporium humuli, occasionally occurred, 

 and an outbreak of the mildew, Sphaerotheca humuli, which does not 

 seem so far to have become a pest of great economic importance as it 

 is in England. 



Horse-chestnut. — The appearance of ragged leaves on this and 

 Maple through injury wrought by frost is described, and the death of 

 a large tree is ascribed to Collyhia velutipes occurring as a w^ound 

 parasite. 



Ampelopsis tricuspidata was attacked by the pycnidial form of 

 Guignardia Bidivellii ( = Phyllosticta lahruscae). 



Belamcanda chinensis was badly attacked by Heterosporium 

 gracile. 



Maple. — The leaves of Acer platanoides were caused to fall prema- 

 turely through the attacks of aphides. This maple is rarely attacked by 

 Rhytism-a acerinum in Long Island, but A. saccharinum suffers 

 severely. A. Pseudoplatanus also appears to escape. 



