. Diseases of plants induced by cryptogamuc parasites; introduction to the study of pathogenic fungi, slime-fungi, bacteria, and algae. English ed. by William G. Smith. Plant diseases; Parasitic plants. 242 ASCOMYCETES. Schizothyrium. The roundish or oblong apothecia dehisce by lobes. The club- slia])ed asci contain oblong, hyaline, two-celled spores. Sch. ptarmicae Desm. (Britain). This occurs as a parasite on living green leaves and stems of Achillea Ptarmica. The apothecia form little black points, which on rupturing break. Fig. 127.—Schizothyrium 2)tarmicae ou Achillea Ptarmica. (v. Tiibeu
. Diseases of plants induced by cryptogamuc parasites; introduction to the study of pathogenic fungi, slime-fungi, bacteria, and algae. English ed. by William G. Smith. Plant diseases; Parasitic plants. 242 ASCOMYCETES. Schizothyrium. The roundish or oblong apothecia dehisce by lobes. The club- slia])ed asci contain oblong, hyaline, two-celled spores. Sch. ptarmicae Desm. (Britain). This occurs as a parasite on living green leaves and stems of Achillea Ptarmica. The apothecia form little black points, which on rupturing break. Fig. 127.—Schizothyrium 2)tarmicae ou Achillea Ptarmica. (v. Tiibeuf del.) up the epidermis into lobes. The thick asci contain two to four large two-celled spores. Paraphyses are present. A pycnidial form is known as Leptothyriuin ptarmicae (Sacc). Rhytisma. The fungi of this genus live in the tissues of living plants and form sclerotial cushions as isolated black spots. In these places the pycnidia are developed, and are followed by apothecia after the death of the leaves. The apothecia open by a fissure, and contain thread-like paraphyses and club-shaped asci with eight needle-shaped spores, which are septate when mature. Rhytisma acerinum (Pers.) (Britain and America). Tow^ards the close of summer, the large black spots caused by this fungus on leaves of various species of Acer (sycamore and maple) are by no means unconnuon. Pycnidia {Melasmia acerinum Lev.), containing little unicellular conidia, are first produced under the cuticle, while the epidermis and under- lying cells become filled with mycelium till a black selerotium. 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-. London Longman's, Green
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectparasit, bookyear1897
