. Comparative morphology and biology of the fungi, mycetozoa and bacteria. Fungi -- Morphology; Bacteria -- Morphology. 276 DIVISION II.—COURSE OF DEVELOPMENT OF FUNGI. one another without interstices, the uppermost inclining towards one another and closing over the apex of the spore-chains ; and as this is done from the first, before the hymcnial layer has reached its definitive breadth, the envelope is formed at least at the same time as the first basidia, and perhaps before them. All cells of the envelope are polyhedric in form, and are distinguished from the spores by their larger size, by
. Comparative morphology and biology of the fungi, mycetozoa and bacteria. Fungi -- Morphology; Bacteria -- Morphology. 276 DIVISION II.—COURSE OF DEVELOPMENT OF FUNGI. one another without interstices, the uppermost inclining towards one another and closing over the apex of the spore-chains ; and as this is done from the first, before the hymcnial layer has reached its definitive breadth, the envelope is formed at least at the same time as the first basidia, and perhaps before them. All cells of the envelope are polyhedric in form, and are distinguished from the spores by their larger size, by their thicker wall which often shows a very delicate prismatic structure, and by their slightly granular or quite pellucid contents, ultimately often containing air. The spore-layer consisting of the spore-chains with the envelope increases in circumference by the constant introduction of new elements from the base and their subsequent enlargement, and encroaches on the surrounding pseudo-parenchyma. Its increase in breadth squeezes the adjacent cells together till they can often be no longer recognised. By its growth in length the summit of the perithecium is first pierced, the epidermis of the host is ruptured, and the spore-layer is raised with the summit of the perithecium above the epidermis and grows, if pro- tected from injury, by constant additions from below into a tube filled with spores and upwards of 1 mm. in length. After it has burst through the epidermis, the cells of the envelope separate from one another at the apex, and the envelope itself opens out into the shape of a cup (Fig. 124 / a), or in some species (Gymnosporangium Sabinae) is split longitudinally into narrow lobes; the upper- most ripe spores fall out, and this disintegration of the envelope and the spore-chains advances in the direction of the base, more rapidly in exposed specimens and when the moisture of the surrounding atmosphere varies than in cultivated and carefully protected plants. The e
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