. Botany for high schools. Botany. 314 GENERAL MORPHOLOGY OF PLANTS spores escape. The wall cells of the capsule contain chlorophyll, and stomates are present in the surface layer. It is thus able to make its own carbohydrate food, but is dependent on the thallus for its water and min- eral food. It is thus more highly developed and special- ized than in the other liver- worts. For this reason the horned livenvorts are by some placed in a separate class, An- thocerotes. 481. Comparative review of the liverworts. — The thallus, or plant body, of the liverworts on which the sex- ual organs are b
. Botany for high schools. Botany. 314 GENERAL MORPHOLOGY OF PLANTS spores escape. The wall cells of the capsule contain chlorophyll, and stomates are present in the surface layer. It is thus able to make its own carbohydrate food, but is dependent on the thallus for its water and min- eral food. It is thus more highly developed and special- ized than in the other liver- worts. For this reason the horned livenvorts are by some placed in a separate class, An- thocerotes. 481. Comparative review of the liverworts. — The thallus, or plant body, of the liverworts on which the sex- ual organs are borne pre- sents t\vo forms. First, the thallose forms in which the plant body is simply a green, leaf-like or strap-shaped structure of very different form in different genera. Second, the foliose forms in which the thallus is more specialized, being differen- tiated into a slender axis with thin, leaf-like expansions. The liverworts are nearly all land forms, adapted to growing on soil and rocks in wet or moist situations, or on logs or tree trunks, some of the latter being adapted to resist dessication in dry sea- sons. The sperm case does not show much advance over that of some of the higher algae, but it is a more massive structure, and the sperms are quite dift'erent and more highly specialized in form. The egg case shows a great advance in structure com- pared with the egg case of the algae, being a multicellular organ, flask-shaped in form. The greatest advance over the algas is. Fig. 292. Anthocer: s gracili=- .4, several gametophytes, on which sporangia have developed; -B, an enlarged sporogonium, showing its elongated character and dehiscence by two valves, leaving exposed the slender columella on the surface of which are the spores; C, D, £, F, elaters of various forms; G, spores. (After Schiffner.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illust
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
