. Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae. Plant diseases; Parasitic plants; Fungi. MELAMPSORA. 367 The patches of Cacoma laricis Hartig,^ appear as golden-yellow cushions on the underside of the needles, The sporophores from which the aecidiospores are abjointed, form the centre of the patch, the periphery being occupied by numerous sterile threads, which grow out as long paraphyses; it may so happen that the whole cushion consists only of these last. The formation of Caeoma- patches is preceded by
. Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae. Plant diseases; Parasitic plants; Fungi. MELAMPSORA. 367 The patches of Cacoma laricis Hartig,^ appear as golden-yellow cushions on the underside of the needles, The sporophores from which the aecidiospores are abjointed, form the centre of the patch, the periphery being occupied by numerous sterile threads, which grow out as long paraphyses; it may so happen that the whole cushion consists only of these last. The formation of Caeoma- patches is preceded by that of little pycnidia (spermogonia), which break out from under the cuticle. The mycelium lives intercellularly, and dies after the shedding of the Caeoma- spores. Melampsora betulina (Pers.) (Britain and America). Uredo- and teleutospores occur on the leaves of the birch {Bctula alba). Plowright^ found from arti- ficial infection that this species produced Caeoma lai^icis on the needles of Larix curopea. A second form of Cacoma laricis was obtained by Hartig, both from infec- tion by Mel. tremulae Tul. from the aspen, and by 3Icl. 2J02yulina Jacq. from the black poplar. Fig. 199. — Mebimpsont M. populina (Jacq.)'^ (Britain and uredospore-LTus?'' (After America). Uredo- and teleutospores found ^uiasne.) on Pojjulus nigra and P. halsamifcra. M. po2mliiia and M. tremulae are probably identical, for Hartig has found the same Melampsora on black and balsam poplars as on aspen, and in each case he produced Caeoma laricis by means of the uredospores. Schroeter states that the Melampsora of Populns nigra produces Cacoma allii of Allium. M. aecidioides D. C. (Britain). Uredo- and teleutospores on leaves of silver poplar {P. alba and P. canescens). Plow- right connects with it a caeo7na-iorm on Mercurialis {Caeoma mercurialis). Schroeter states that the Melampsora of Populus tremula produces Caeoma mercurialis. The Mclampsorae of Willows were until recently grouped under a
Size: 1696px × 1473px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublisherl, booksubjectfungi
