10 THOMAS: INFECTION OF APIUM GRAVEOLENS 
plants. Whether there are other strains of the fungus which in- 
fect both celery and parsley is a question of interest, both theoret- 
ically and practically, and should receive further attention. The 
various other hosts tested were grown in pots in the greenhouse 
and inoculated with celery plants in every case to check on the 
conditions for infection. The following plants were tested: 
UMBELLIFERAE 
Anethum graveolens L., dill 
Anthriscus cerefolium (L) Hoffm., chervil (beaked parsley) 
Carum Carvi L., caraway 
Coriandrum sativum L., coriander 
Cryptotaenia canadensis (L.) DC., hone wort 
Daucus Carota L., carrot (both wild and cultivated) 
Foeniculum officinale All., fennel 
Osmorhiza sp., sweet cicely 
Pastinaca sativa L., parsnip 
Petroselinum sativum Hoftm.., parsley (plain leaf, curly leaf, 
and Hamburg varieties) 
Silaus Besseri 
MISCELLANEOUS 
Antirrhinum majus L., snapdragon 
Beia vulgaris L., beet (sugar and garden varieties) 
Lactuca sativa L., lettuce 
Lobelia sp. 
Lycopersicum esculentum Mill., tomato 
Nicotiana Tabacum L., tobacco 
Pisum sativum L., pea 
None of the plants listed here developed any sign of infection. 
From these data it must be concluded that the Septoria of celery 
has reached a comparatively high degree of specialization as to 
its hosts. These results agree essentially with those of Beach (1), 
working with.a considerable number of other species of the genus 
Septoria. ‘ 
EFFECT OF FERTILIZERS UPON INFECTION 
Realizing that the terms health, vigor, and vitality are vague 
and difficult of definition in plants as in animals, I have attempted 
