. Comparative morphology of Fungi. Fungi. 98 COMPARATIVE MORPHOLOGY OF FUNGI ! â ' gemmae generally arise endogenously; multinucleate protoplasmic por- tions of varying circumferences, draw together and, inside the original hyphal membrane, surround themselves with a special thick wall. The stipitate gemmae (mycelial conidia, stylospores) of Mortierella and Syn- cephalis are cut off in scattered or racemose groups on short branches of the mycelium (H. Bachmann, 1900). Under suitable conditions both gem- mae and sclerotia develop to new mycelia. Asexual reproduction takes place through spor- an
. Comparative morphology of Fungi. Fungi. 98 COMPARATIVE MORPHOLOGY OF FUNGI ! â ' gemmae generally arise endogenously; multinucleate protoplasmic por- tions of varying circumferences, draw together and, inside the original hyphal membrane, surround themselves with a special thick wall. The stipitate gemmae (mycelial conidia, stylospores) of Mortierella and Syn- cephalis are cut off in scattered or racemose groups on short branches of the mycelium (H. Bachmann, 1900). Under suitable conditions both gem- mae and sclerotia develop to new mycelia. Asexual reproduction takes place through spor- angia with sporangiospores. The parts of the mycelium from which the sporangia develop swell considerably and their nuclei divide repeatedly. In forms with stolons, the sporangiophores branch almost exclusively from the nodes (Fig. 55, 1) and are then firmly attached to the substrate by the group of rhizoids; but in Absidia they branch directly from the stolons, midway between nodes. In Mortierella Rostafinskii (Brefeld, 1881) the rhi- zoids develop so luxuriantly that they surround the lower quarter of the sporangiophore like a thick sheath (Fig. 57); their outer wall is yellow or brown and cuticularized so that the whole structure looks like a capsule. In the lower species, the sporangiophores are unbranched; in the higher species, they are forked, racemose, corymbose, cincinnal, etc. The tip of each branch swells up to a sporangium, allowing the protoplasm and nuclei of the swollen hyphal portion to migrate into it, and is finally abjointed. In the subfamily of the Mortierelleae, this septum FIG- 57. â Mortierella is plane or slightly bent, like a watch glass; in the Rostafinskii. Sporangio- Mucoreae, Piloboleae, etc., it is arched far into phore surrounded by hy- . phae, h, at base, t, in the sporangium (Fig. 54, 2 and 3). 1 his peculiar sheath; a, end of stolon. dome (columella) is generally smooth, cylindrical (X 100; after Brefeld.) \ ' t. â . du or pynlorm and even aft
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