. Text-book of botany, morphological and physiological. Botany. FIG. 240.—Riccia g-lauca; A apical region in vertical longitudinal section; ar archegonium; c oosphere (X 560); B the unripe sporogonium sg surrounded by the calyptra, which still bears the neck of the arche- gonium ar {x 300, after Hofmeister).. FIG. 240 bis. — Cell-forms of Marchantia polymorpha with thickenings; A an elater (one-half) from the sporogonium, with two spiral bands; A' a portion more strongly magnified; B a parenchyma-cell from the centre of the thal- lus, with thickenings projecting inwards in a reticulate manner;
. Text-book of botany, morphological and physiological. Botany. FIG. 240.—Riccia g-lauca; A apical region in vertical longitudinal section; ar archegonium; c oosphere (X 560); B the unripe sporogonium sg surrounded by the calyptra, which still bears the neck of the arche- gonium ar {x 300, after Hofmeister).. FIG. 240 bis. — Cell-forms of Marchantia polymorpha with thickenings; A an elater (one-half) from the sporogonium, with two spiral bands; A' a portion more strongly magnified; B a parenchyma-cell from the centre of the thal- lus, with thickenings projecting inwards in a reticulate manner; C a slender root-hair with thickenings projecting inwards, these are ar- ranged on a spiral constriction of the cell-wall; at D a thicker-root-hair, with -thicker branched pro- jections, and spiral arrangement still more evi- dent. several layers; the under side produces a number of hairs with conical thickenings projecting inwards placed upon a spiral constriction of the internal cavity (Fig. 240, bis, C), and also two rows of leaf-like lamellae, like the Riccieae. The upper side is covered by a very distinctly differentiated epidermis, penetrated by large stomata1 of peculiar form. Each of these stands, in Marchantia, Lunularia, &c, in the centre of a rhombic plate; these plates are parts of the epidermis which overarch large air-cavities, from the bottom of which the cells containing chlorophyll spring in af conferva-like manner, while the rest of the tissue is destitute of chlorophyll and consists of long horizontal cells without interstices (cf. Fig. 65). 1 These stomata are formed (see Fig. 89) by the simple separation from one another of four or more epidermal cells which afterwards are divided by walls parallel to the surface of the thallus. (Leitgeb.). 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 origin
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1882
