. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. iia DIVISION I.—GENERAL MORPHOLOOr. A more noteworthy special case which recalls the formation of swarm-spores is that of the germination of the acrogenously formed spores (gonidia) of the plasmato- parous Peronosporeae (Peronospora densa, Rab. and P. pygmaea, Unger); here when a spore is placed in water the whole of the protoplasm suddenly swells and issues from the papilla-like tip of the spore which opens to admit its passage, and assumes the form of a spherical bo
. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. iia DIVISION I.—GENERAL MORPHOLOOr. A more noteworthy special case which recalls the formation of swarm-spores is that of the germination of the acrogenously formed spores (gonidia) of the plasmato- parous Peronosporeae (Peronospora densa, Rab. and P. pygmaea, Unger); here when a spore is placed in water the whole of the protoplasm suddenly swells and issues from the papilla-like tip of the spore which opens to admit its passage, and assumes the form of a spherical body, which invests itself at once with a new and delicate cellulose-membrane and then puts out a simple germ-tube. The number of the germ-tubes which proceed from a single spore is usually small, 1,2, or 3, seldom only a few more. The germination of the spores of the genera Pertusaria, Ochrolechia, Mass. and Megalospora, Mass., first observed by Tulasne' and more closely examined by myself ^ is therefore all the more striking. These spores which. Fig. 57. ti—rf. Megntospora ajjinis, Kbr. a a ripe ejected spore, h—«/successives tages of germination on a moist microscopic slide; b and c opticallongitudinal sections only, in rf the surface also is seen, e—/ Ochrolechia faltescais, Mass. i * lirst beginning of germination in optical longitudinal section,ywith elongated germ-tubes, g Pertusaria deBaryana, Hepp.: optical longitudinal section through the half of a spore which is just begimiing to germinate, showing the canals with their enlargements in the walL The specimen was treated with glycerine; the wall with its cavities appeared when fresh as in £; the contents of the spore are omitted, /"magn. 190, the other figures 390 times. are formed in asci (Figs. 57, 59 A,B) are unusually large (in some species 180 fi and more in length) and ovoid or ellipsoidal, filled with a dense oily protoplasm and sur- rounded by a thick colourless stratified membrane usually of many
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