. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. 466 FUNGI IMPERFECTI. stricted tissue will be found extending quite round the twig (Fig. 293). At these places the bark and cambium have been killed, whereas the higher portions of the twig have continued to increase in thickness. Numerous small black pycnidia break out on the bark of diseased places and give off small unicellular spindle-shaped conidia, which convey infection to new hosts in August or September. Ki
. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. 466 FUNGI IMPERFECTI. stricted tissue will be found extending quite round the twig (Fig. 293). At these places the bark and cambium have been killed, whereas the higher portions of the twig have continued to increase in thickness. Numerous small black pycnidia break out on the bark of diseased places and give off small unicellular spindle-shaped conidia, which convey infection to new hosts in August or September. Killed branches die and dry up without casting their needles.^ Ph. pithya Sacc. causes a disease similar to the preceding on the Douglas fir {Psendots^iga Douglasii). The pycnidia of the fungus are found on dead constricted parts of twigs, and they, as well as other symptoms of the disease, closely resemble those of Phoma ahietina. Eostrup^ defined and de- scribed it as Ph. pithya Sacc. Magnus also re- cords it on branches of Piniis sylvestris in Berlin botanic garden. Other species of Phoma frequent other conifers and broad-. FlG. 293.—Phoma alietina. Twig of Silver Fir show- ing ihe constriction characteristic of this disease, dotted over with pycnidia. (After R. Hartig.) ^Bohm (Zeitsch. f. Forst- u, Jagd-wesen, 1896, p. 154) describes and figures an attack of this parasite on Pseudotstiga Douglasii in North Germany. One cannot, however, avoid suggesting some confusion between this and Ph. pithya described next. (Edit.) ^E. Rostrup Undersoegelser over Snyltes vampes Angreb paa Skovtraeer, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Tubeuf, Karl, freiherr von, 1862-1941; Smith, William G. London ; New York [etc. ] : Longmans, Green & co.
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