. A textbook of botany for colleges and universities ... Botany. REPRODUCTION AND DISPERSAL 813 turgor, whereupon the escaping water tears loose the sporangium and expels it with the enclosed spores for some distance. In a somewhat similar fashion are expelled the conidia of Entomophthora and the ascospores of Ascoholus and of Peziza repanda. In the ergot fungus (Claviceps) a sweetish substance, known as honey dew, is se- creted as the conidia ripen, and insects visiting the fungus for the honey dew scatter the spores. In the stinkhorn fungus {Phallus impudicus) the spore-bearing portion deliq
. A textbook of botany for colleges and universities ... Botany. REPRODUCTION AND DISPERSAL 813 turgor, whereupon the escaping water tears loose the sporangium and expels it with the enclosed spores for some distance. In a somewhat similar fashion are expelled the conidia of Entomophthora and the ascospores of Ascoholus and of Peziza repanda. In the ergot fungus (Claviceps) a sweetish substance, known as honey dew, is se- creted as the conidia ripen, and insects visiting the fungus for the honey dew scatter the spores. In the stinkhorn fungus {Phallus impudicus) the spore-bearing portion deliquesces into a vile-smelling mass that attracts flies, which scatter the spores. Doubtless • many fungus spores also ad- here to the slimy surface of slugs and thereby are scattered. Flies are among the most effi- cient scatterers of spores, which become attached to various parts of the body, and occur abundantly in the excreta ; the spores or propagules of more than fifty species of fungi and bacteria have been found in a single fly speck. Many fungus spores are able to endure severe conditions. For example, the spores of Mucor and of Aspergillus have been dried for two years, after which they were exposed tor three weeks to a temperature of —180° C , and for three days to — 253° C, without impair- ing their capacity for germi- nation. Desiccated bacteria have been known to retain their vitality tor nearly a hun- dred years. It is concluded from such experiments that all vital activity may be suspended for long periods of time (p. 909). In part this endurance is due to unexplained features in the resting protoplasm, but there are also many instances of protective structures or habits. In most ascomycetes the spores, though thin- walled, are protected within the ascocarps (as in lichens and mildews, figs. 181,182), while in many hymenomycetes the thin-walled basidiospores are protected by the pileus ; some of the so-called bracket fungi are hard and woody and capable of
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
