. Essentials of botany. Botany; Botany. 270 ESSENTIALS OF BOTANY 347. Minute Structure of the Sporophyte. — Pick out from old re- ceptacles some of the full-grown sporophytes, mount, and examine with Note: (a) The foot (which was imbedded in the receptacle), the slender stalk, and the enlarged spore-case. Draw. (6) Spores. (c) Elaters, spirally-marked cells which assist in scattering the spores. Draw (J) and (c) under 348. Discussion Marchantia is far more highly spe- cialized for utilizing the raw materials of plant food than are any of the algae or fungi studied in previous section
. Essentials of botany. Botany; Botany. 270 ESSENTIALS OF BOTANY 347. Minute Structure of the Sporophyte. — Pick out from old re- ceptacles some of the full-grown sporophytes, mount, and examine with Note: (a) The foot (which was imbedded in the receptacle), the slender stalk, and the enlarged spore-case. Draw. (6) Spores. (c) Elaters, spirally-marked cells which assist in scattering the spores. Draw (J) and (c) under 348. Discussion Marchantia is far more highly spe- cialized for utilizing the raw materials of plant food than are any of the algae or fungi studied in previous sections. Its thallus has a well-defined epidermis, especially firm on the upper surface to pre- vent undue loss of water. The rhizoids are efficient in absorbing water containing nutrient substances from the earth. The air-cham- bers beneath the upper sur- face of the thallus, with their hair-like chlorophyll apparatus, are admirably adapted for photosynthesis. Asexual reproduction is well attained by the separation of young branches (set free by the dying of the older parts) and by the numer- ous buds. The sexual reproduction is of a complicated character, brought about by the conjugation of unlike gametes. 349. Alternation of Generations. — In the reproduction of Marchantia for the first time in the studies of spore- plants outlined in Chapters xxiii-xxvn, the student fully. Pig. 195. Frullania, a Leafy Liver wort, growing on maple bark (About 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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