. Essentials of botany. Botany; Botany. 262 ESSENTIALS OF BOTANY and some of them parasitic. A few may live in either fasliion at will. The mycelium through which the plant obtains its nourishment is often so fine and inconspicuous that it escapes notice, and the fruiting portion, is com- monly thought to spring directly from the earth, bark, wood, or other substratum to which it is attached. The reproduction is wholly asexual. Gill fungi are of consider- able economic importance. A good many are edible (though others which resemble them are actively poisonous). Such par- asitic species as Arm
. Essentials of botany. Botany; Botany. 262 ESSENTIALS OF BOTANY and some of them parasitic. A few may live in either fasliion at will. The mycelium through which the plant obtains its nourishment is often so fine and inconspicuous that it escapes notice, and the fruiting portion, is com- monly thought to spring directly from the earth, bark, wood, or other substratum to which it is attached. The reproduction is wholly asexual. Gill fungi are of consider- able economic importance. A good many are edible (though others which resemble them are actively poisonous). Such par- asitic species as Armillaria mel- lea (Fig. 185) are very injurious to timber. This fungus sends its mycelium through the bark or between the bark and wood of trees and often causes the death of the host. A large shelf-fungus (2Va- metes JPini) of a closely related group (Fig. 184) is very destruc- tive to trees of the Pine famil}-. The lack of sexual reproduc- tion in organisms as compli- cated as the gill fungi seems to be evidence that these forms are degenerating. The same conclusion is suggested by the occurrence of what appears to be imperfect reproductive apparatus of Puccinia on the upper surfaces of infected barberry leaves. There is much other evidence of the same sort, and it all agrees with the supposition that fungi are degenerate descendants. Fig. 187. Part of the Preceding Pigure. (x about 300.)- C, layer of cells immediately under the hymenium. s, 5', s", three successive stages in growth of 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 perfectly resemble the original Bergen, Joseph Y. (Joseph Young), 1851-1917. Boston, Ginn
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