. Introduction to structural and systematic botany, and vegetable physiology. Botany. CEYPTOGAMOUS OR FLOWEKLESS PLANTS. 505 sporangia from the under side: these open variously, but are not four-valved. Elaters with two spiral 977. Sul)Ord. Jungermanniacea!. Frondose or mostly foliaceous plants; with the sporangium dehiscent into four valves, and' the spores mixed with elaters. Class V. Thallophytes. Vegetables composed of parenchyma alone, forming a mass or stratum (thallus, 109, 727), or consisting of a congeries of cells, or even of separate cells, never exhibiting a marked distinc
. Introduction to structural and systematic botany, and vegetable physiology. Botany. CEYPTOGAMOUS OR FLOWEKLESS PLANTS. 505 sporangia from the under side: these open variously, but are not four-valved. Elaters with two spiral 977. Sul)Ord. Jungermanniacea!. Frondose or mostly foliaceous plants; with the sporangium dehiscent into four valves, and' the spores mixed with elaters. Class V. Thallophytes. Vegetables composed of parenchyma alone, forming a mass or stratum (thallus, 109, 727), or consisting of a congeries of cells, or even of separate cells, never exhibiting a marked distinction into root, stem, and foliage, or into axis and leaves. 978. Ol'di Hellenes (Zdchens) form the highest grade of this lower series. They consist of flat expansions, which are rather crustaceous than foliaceous ; while some are nearly pulverulent. In several the vegetation rises into a kind of axis, or imitates stems and branches; as in the Cladonia coccinea, which abounds on old logs (Fig. 1327) ; or in Cladonia rangiferina, the Reindeer Moss ; also in Usnea, where it forms long, gray tufts, hanging from the boughs of old trees in our Northern forests. Lichens are never aquatic, but grow on the ground, on the bark of trees, or on exposed rocks, to which the proper rock- Lichens adhere by their lower surface, with great tenacity, while by FIG. 1319. Steetzia Lyellii, with the young fructification still included in the tubular peri- anth, 1820. Dehiscent sporangium of a Jungermannia, on its fruit-stalk, with some of the leaves at its base, magnified enough to exhibit its cellular structure. 1321. Two elaters from the same (a, iu an entire state ; &, with only the threads remaining), and some spores, highly magnified. 43. 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 Gray, Asa, 1810-1888. New York [etc
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Keywords: ., bookauthorgra, bookcentury1800, bookdecade1850, booksubjectbotany
