. Essentials of botany. Botany; Botany. Fig. 178. A Lichen (Xantkoria). (Natural size.) sufSciently distinct so that lichens are best considered by themselves for purposes of study and classification. The relation of the fungus and its algal host is not that of destructive parasitism, but rather a mutual rela- tion (symbiosis) in which both fungus and alga may have a vigorous growth. The relationship has been investi- gated in various ways, and it has been found that, while the alga may thrive independent of the fungus, the ger- minating fungus spores can grow only to a limited extent if depri
. Essentials of botany. Botany; Botany. Fig. 178. A Lichen (Xantkoria). (Natural size.) sufSciently distinct so that lichens are best considered by themselves for purposes of study and classification. The relation of the fungus and its algal host is not that of destructive parasitism, but rather a mutual rela- tion (symbiosis) in which both fungus and alga may have a vigorous growth. The relationship has been investi- gated in various ways, and it has been found that, while the alga may thrive independent of the fungus, the ger- minating fungus spores can grow only to a limited extent if deprived of the algal host; but if supplied naturally or artificially with the proper alga they make a normal growth. The same alga may serve as gonidia to a number of lichens, often of very different form, and while the number of lichens reaches into the thousands, the number of algse known to serve as gonidia is quite small. Lichens are widely distrib- uted in all zones but flourish particularly in northern re- gions where other vegetation is scanty. Some were for- merly important as sources of dyes. " Iceland moss " is a lichen used for food, and a finely branching form, growing in extensive mats ou. Fig. 179. A Lichen (TIsnea). (Natural size.). 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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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1908
