Elementary botany (1898) Elementary botany elementarybotany00atki Year: 1898 122 MORPHOLOGY. rangium becomes dissolved, except a small collar around the stalk which remains attached below the columella (fig. 133). Fig. 132. Group of sporangia of a mucor (Rhizopus nigricans) showing rhizoids and the stolon extend- ing from an older group. By this means the gonidia are freed. These gonidia germinate and produce the mycelium again. 277. Sexual stage.—This stage is not so frequently found, but may some- times be obtained by growing the fungus on bread. Conjugation takes place in this way. Two
Elementary botany (1898) Elementary botany elementarybotany00atki Year: 1898 122 MORPHOLOGY. rangium becomes dissolved, except a small collar around the stalk which remains attached below the columella (fig. 133). Fig. 132. Group of sporangia of a mucor (Rhizopus nigricans) showing rhizoids and the stolon extend- ing from an older group. By this means the gonidia are freed. These gonidia germinate and produce the mycelium again. 277. Sexual stage.—This stage is not so frequently found, but may some- times be obtained by growing the fungus on bread. Conjugation takes place in this way. Two threads of the mycelium which lie near each other put out each a short branch which is clavate in form. The ends of these branches meet, and in each a septum is formed which cuts off a portion of the protoplasm in the end from that of the rest of the my- celium. The meeting walls of the branches now dissolve and the protoplasm of each gamete fuses into one mass. A thick wall is now formed around this mass, and the outer layer becomes rough and brown. This i- the zygote ox zygospore. The mycelium dies and it becomes free often with the suspensors, as the stalks ot these sexual brandies are called, still attached. This zygo- spore passes through a period of rest, when with the entrance of favorable conditions of growth it germinates, and usually produces directly a sporan- gium with gonidia. This completes the normal lite cycle of the plant. 278. Gemmae, as they are sometimes called, are often formed 01 the mycelium. A short cell with a stout wall is formed on the side of ;
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