. Botany for high schools and colleges. Botany. CaHLOBLASTEu^. 353 oosphere immediately begins to secrete a wall of cellulose about itself, and it thus becomes an oospore {F, Fig. 170). According to Pringsheim, the oospore remains for three months in a resting state before germinating; in the latter process the out&r coat of the spore splits, and through the opening a tube grows out which eventually assumes the form and dimensions of the full-grown Fig. 170.—Sexual ortrana of Yaucheria sessilis. A, beE:inning of the formation of tlie oogonium (orf) and antherifiinm (A) upon tiie br
. Botany for high schools and colleges. Botany. CaHLOBLASTEu^. 353 oosphere immediately begins to secrete a wall of cellulose about itself, and it thus becomes an oospore {F, Fig. 170). According to Pringsheim, the oospore remains for three months in a resting state before germinating; in the latter process the out&r coat of the spore splits, and through the opening a tube grows out which eventually assumes the form and dimensions of the full-grown Fig. 170.—Sexual ortrana of Yaucheria sessilis. A, beE:inning of the formation of tlie oogonium (orf) and antherifiinm (A) upon tiie branch b, S, later Biage of the same, the antheridium (a) now separated from the main branch (6) by a transverse par- tition. C. an open oogonium expelling a drop of mucilage, si. D, spermatozoids. £", spermatozoids collected at the mouth of the oogonium. F, the antheridium, a, col- lapsed after the escape of the ppermatozoids ; osp, the oospore. X about 100, except Dj which ismuch more.—C, X>, after Pringsheim, the others after Sachs. (a) The formation of zoospores begins in tlie niglit, tliey escape in the morninfT, and the night following they germinate. (6) The formation of sexual organs begins in the evening, and is completed the next morning ; fertilization takes place during the day {from 10 to 4 ). (c) Good specimens of VaucAeria may be found clothing the boggy ground about many springs. The bright green mats may be trans- ferred to the aquarium for the study of zoospores ; but for the sexual organs the dingy and dirty looking specimens must be 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 Bessey, Charles E. (Charles Edwin), 1845-1915. New York : H. Holt
Size: 1776px × 1407px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1888
