. A practical course in botany, with especial reference to its bearings on agriculture, economics, and sanitation. Botany. CRYPTOGAMS 329 4. Do you find fungi most abundant on young and healthy trees, or on old, decrepit ones ? Account for the difference. (141,343,378.) 5. Do you ever find them growing on perfectly sound wood anywhere ? 6. Are they ever beneficial to a tree ? (86.) 7. Is it wise to leave old, unhealthy trees and decaying trunks in a timber lot? IV. LICHENS Material. — Specimens can be found almost everywhere, growing on rocks, walls, logs, stumps, and trees. Some of the more c
. A practical course in botany, with especial reference to its bearings on agriculture, economics, and sanitation. Botany. CRYPTOGAMS 329 4. Do you find fungi most abundant on young and healthy trees, or on old, decrepit ones ? Account for the difference. (141,343,378.) 5. Do you ever find them growing on perfectly sound wood anywhere ? 6. Are they ever beneficial to a tree ? (86.) 7. Is it wise to leave old, unhealthy trees and decaying trunks in a timber lot? IV. LICHENS Material. — Specimens can be found almost everywhere, growing on rocks, walls, logs, stumps, and trees. Some of the more common kind are: Parmelia, recognizable by the shallow spore cups borne on the upper surface of the thallus; Cladonia, by the little stalked receptacles, like goblets, in which its spores are held; Physcia, by its bright orange color. Where practicable, it is well to have several different kinds for comparison. Iceland moss (Cetraria islandica) can generally be obtained from the grocers, and is a good example of an intermediate form between foliaeeous and fruticose lichens. If the specimens are very dry, they will be too brittle to handle conven- iently, and should be moistened by soaking a short time in water. This will render them quite flexible and also bring out the green color more clearly. 379. Examination of a typical specimen. — The com- monest kind of lichens, and generally the most easily ob-. A B Fig. 469.—Foliaeeous lichens: A, Xanthoria {Physcia) parietina; B, Parmelia conspersa; a, spore cups. fcained, are those that grow on rocks and tree trunks in flat, spreading patches. Their margins are much dented and. 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 Andrews, Eliza Frances, b. 1840; Lloyd, Francis Ernest, 1868-1947. ed. New York, Cincinnati [etc. ] American book company
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