. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. 258 ASCOMYCETES. conidia germinate and give off long septate hyphae which, follow- ing the course of the pollen-tube, reach the ovary, and soon iill all four loculi with a white mycelium. The growth of this mycelium proceeds from the central axis towards the walls, and forms a hollow sphere open above and below. The diseased berries cannot be distinguished till ripe; then, whereas the normal are red, the diseased ar
. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. 258 ASCOMYCETES. conidia germinate and give off long septate hyphae which, follow- ing the course of the pollen-tube, reach the ovary, and soon iill all four loculi with a white mycelium. The growth of this mycelium proceeds from the central axis towards the walls, and forms a hollow sphere open above and below. The diseased berries cannot be distinguished till ripe; then, whereas the normal are red, the diseased are yellowish-brown to chestnut- coloured, and soon shrink up, leaving only the outline of the sclerotium. The dead or mummified berries fall prematurely, and lie over winter on the earth. In April or May, the sclerotia give rise. Fig. 136.—Sclerotinia oxycocci on Vaccinium Oxyeoccus. Toung shoot of Cran- berry with mature conidial cushion and diseased upper leaves. A, Peziza-cup developed from a sclerotial fruit; numerous rliizoids proceed from the base of the stalk. B, Ascospores in stages of germination. C, Conidia in germination, with remains of disjunctors still attached. (After Woronin.) to several primordia or horn-like stalks, on the extremity of which an apothecium is afterwards formed. Ehizoids are pro- duced at the base of the stalk and attaching themselves to the ground act as supports and organs of nutrition. The apothecia contain both asci and paraphyses; the latter are septate, dichoto- mously branched filaments, with club-shaped ends, and coated with a brown resinous substance. The asci have a canal at one end through which are ejaculated eight spores of almost equal size. These produce sporidia in water; in nutritive solutions, however, they form a septate mycelium with conidia. The ascospores bring about infection by means of one or two germ-tubes which penetrate the outer membranes of young. Please note that these images are extracted from scanned page images
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherl, booksubjectfungi
