The Water-Relation of Puccinia Asparagi. A Contribution to the Biology of a Parasitic Fungus

Ralph E. Smith
1904 Botanical Gazette  
WHETHER the use of the term "ecology" would be consistent and proper throughout the present article, the writer must confess his inability to decide. With plants of independent existence ecology has become a well-defined branch of botanical science, but when complicated with the phenomena of parasitism there must be distinguished two fairly distinct classes of life-relations; those which act upon the parasitic organism directly, and those which affect it, even more decidedly perhaps, in a
more » ... perhaps, in a secondary or indirect manner through their effects upon the host-plant. "Biology," in the European sense, seems on the whole a more fitting term for the present purpose; since at many points it is difficult to say whether we are considering the relation of the parasite to its environment, or to its host's environment, or whether its host is its environment. The subject is one of ecology in the broadest sense, yet a distinction must be made between the relations of an organism to natural influences, and its relations to the effects of perhaps the same influences upon another organism upon which it lives as a parasite. The fungus has no soil-relation, of course, but its connection with the host-plant is much more than this, though corresponding to a certain extent. Without extended discussion on this point, it will suffice to say that it has seemed to the writer very desirable to establish upon a systematic basis the relations existing between parasitic fungi in general and the various influences exerted upon them in nature, either directly or acting through the medium of the host-plant. While many scattered observations of this kind exist, very little definite work has been done in establishing general principles or in drawing definite conclusions. The observations contained herein are offered as a modest contribution in this direction. It is well established in a general way that the development of I904] I9
doi:10.1086/328519 fatcat:ald4y2ua4fg5zjz5bh57gpyc2i