Text-book of botany, morphological and physiological . of the cells thus formed, which have somewhat theshape of a flask, is an antheridium; its entire contents form a spermatozoid {%) of oval ALGM. 233 shape with two cilia ; it is endowed with motion like a swarm-spore, but its entranceinto the oogonium has not yet been observed. The effect of fertilisation is seen inthe oogonium by its contents becoming surrounded with a membrane of its own, formingthe oospore. This now grows considerably, and at the same time the formation of thecortical layer (r) of the oogonium commences, while out of the
Text-book of botany, morphological and physiological . of the cells thus formed, which have somewhat theshape of a flask, is an antheridium; its entire contents form a spermatozoid {%) of oval ALGM. 233 shape with two cilia ; it is endowed with motion like a swarm-spore, but its entranceinto the oogonium has not yet been observed. The effect of fertilisation is seen inthe oogonium by its contents becoming surrounded with a membrane of its own, formingthe oospore. This now grows considerably, and at the same time the formation of thecortical layer (r) of the oogonium commences, while out of the cells thatsupport it pro-ceed branches (A, og) which cling closely to it. These again form branches which alsocling closely and divide transversely; the branchlets of other branches also ramify (B);and only the neck of the oogonium does not become covered with the cortical this happens between INlay and July; later, the contents of the remaining cells ofthe i)lant disappear, and the walls of the cortical layer of the oogonium assume a deep. Fig. 165.—^/ part of a fertile thallus of Coleochate pi4lvinata (X3S0); B ripe oogonium enclosed in its cortical layer;C germinating oogonium, in the cells of which the swarm-spores are formed ; D swarm-spores (B-D x 280) (afterPringsheini). dark-brown colour. The further development of the oospore within the oogoniumnow covered with its cortical layer begins only in the next spring; a parenchymatoustissue is formed by successive bipartitions; the cortical layer splits and is thrown off(Fig. 165, C); and from each cell arises an ordinary swarm-spore, and from this again anasexual plant. C. scutata (the most abnormal species) deviates from these processesonly so far that in it the oogonia provided with their cortical layer lie on the surfaceof the disc, and the antheridia are the result of divisions of disc-cells into fours. The Floride.^^ are a group of Algae of extraordinarily variable form, belonging,with few exceptions (Batra
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
