. Comparative morphology of Fungi. Fungi. OOMYCETES 55 tions, M. brachyandra forms moniliform gemmae with thick, brownish walls. Reproduction takes place by zoospores and oogonia with antheri- dia (Thaxter, 1895; Lagerheim, 1899; Woronin, 1904; Laibach, 1926). The zoospores develop as follows: In the upper, often somewhat thickened part of a hypha, protoplasm with numerous nuclei collects, and is abjointed from the vacuolate portion. By its cleavage, there are formed one or two series of uninucleate zoospore initials which become zoospores in an unknown manner and swarm through an opening at t
. Comparative morphology of Fungi. Fungi. OOMYCETES 55 tions, M. brachyandra forms moniliform gemmae with thick, brownish walls. Reproduction takes place by zoospores and oogonia with antheri- dia (Thaxter, 1895; Lagerheim, 1899; Woronin, 1904; Laibach, 1926). The zoospores develop as follows: In the upper, often somewhat thickened part of a hypha, protoplasm with numerous nuclei collects, and is abjointed from the vacuolate portion. By its cleavage, there are formed one or two series of uninucleate zoospore initials which become zoospores in an unknown manner and swarm through an opening at the tip of the sporangium (Fig. 34, a). After some time they come to rest, surround themselves with a membrane and germinate. Subsequently many lateral sporangia may grow out behind each other, so that generally. Fig. 34.—Monoblepharis macrandra. a, Zoosporangium; M. sphaerica. b to e, Fertilization; Og, oogonia; An, antheridia producing sperms; S, oospores. (After Woronin, 1904.) only a portion of the hyphae participates in sporangial formation; thus sporangial conditions result which give the impression of sympodial branching. In other cases proliferation occurs, , a new sporangium arises beneath an old one and grows through its empty membrane. The antheridia are epigynous in Monoblepharis insignis, and M. brachyandra, hypogynous in M. spherica and M. macrandra (Fig. 34, 6). In the first, the antheridium, like a zoosporangium, is cut off as a terminal cell. The hypha below the septum forms a lateral outgrowth, the neck of the oogonium, and the oogonium itself is abjointed from the rest of the hypha. Thus the antheridium is borne on the oogonium. A new lateral outgrowth develops beneath the oogonium; its tip is separated as an antheridium while the remainder swells to an oogonium and is. 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 perfe
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