104 
IOWA ACADEMY OF SCIENCE Voi,. XXVIi, 1920 
Melanconium spic-carpon Lk. On stems of Almis sitchensis. 
Pestalozzia lignicola Cke. On stems of Salix purpurea. 
Pestalozzia truncata Lev. On stems of Salix purpurea. 
Pestalozzia truncata ruhi Karst. On stems of Rubus strigosus. 
Moniliaceae 
Aspergillus sp. On leaves and stems of Rubus strigosus. 
Botrytis cinerea Pers. {B. vulgaris Fr.) On Apium graveolens, A. 
petroselinum, Brassica oleracea and vars., Calendula officinalis, Calliste- 
phus hortensis, Cheiranthus cheiri, Coleopleurum gmelini, Coreopsis sp., 
Dianthus caryophyllus, D. hedwigi, Dimorphotheca aurantiaca, Bschscholtzia 
calif ornica, Euphorbia pulcherrima. Frag aria spp., Heliotr opium peruvi- 
anum, Iberis umbellata, Lactuca sativa, Lathyrus odoratus, Linaria cym- 
ballaria, Lobelia erinus, Lycopersicum cerasiforme, L. esculentum, Mathi- 
ola incana annua, Mimulus lutens, Myrsiphyllum asparegoides, Nicotiana 
tabacum, Papaver spp., Prunus spp., Ribes aureum, R. nigrum, R. triste, 
R. vulgare, Rosa spp,, Rubus idaeus, R. parviflorum, R. strigosus, Solanum 
tuberosum, Tagetes ere eta, Thymus officinalis, Tropaeolum mafus, Vicia 
fabia, Viola tricolor. Zinnia elegans. 
The above list, though a long one is by no means complete. The 
writer at first started to preserve specimens of all species affected but 
soon dispaired as there seemed to be no species of flowering plant im- 
mune. Though a weak parasite it is easily the most destructive fungus 
of southeastern Alaska. The conidia do not seem able to directly infect 
vigorous and healthy parts of plants but will readily infect weakened 
or dying parts and where these come in contact with healthy tissues the 
mycelium rapidly spreads. One of the commonest initial infections is 
in the fading petals of the flowers. Where these fall on the leaves the 
leaves soon become infected and the fungus often reaches the stem through 
the petiole, resulting in the| girdling of the stem and the death of the 
parts above. Old leaves that have lost their vigor are also direttly 
infected. The fungus is easily transferred from one species to another 
when the infected portions of one species come in contact with tissues 
of the other. The fungus seems to spread more rapidly in the tissues 
of some hosts than in others. Weather conditions are a potent factor 
in the spread of the parasite as it is much more destructive during pro- 
longed cloudy and rainy weather than during bright clear weather. During 
prolonged spells of wet weather some kinds of plants will be almost 
ruined. Several bright days in succession very noticeably^ check the 
ravages of the fungus. The crop of garden currants was very much 
reduced one season by its ravages owing to unfavorable weather at 
blooming time. As a rule it is worse in the greenhouse than outside. 
During prolonged cloudy weather it is sometimes necessary to fire up 
in order to reduce the humidity of the air in the greenhouse even during 
the summer. This is also our chief damping off fungus. 
Oospora scabies Thaxter. Potato Scab. On tubers of Solanum tuber- 
osum. Quite common in some soils. 
Ramularia heraclei (Oud.) Sacc. On leaves of Heracleum lanatum. 
Ramularia tulasnei Sacc. See Mycosphaerella fragariae. 
Ramularia sp. On leaves of Plantago major. 
