. Botany for high schools and colleges. Botany. 43 BOTANY. the whole of the protoplasm of the mother-cell is used. The former he calls Pree-Cell Formation,&ni. the latter Formation of Cells by Division, of the Mother- Oell, and includes also under the last a part of what has been described above under the head of Fission. It is doubtful, however, whether such a division is of much importance. (6) What has been called the Rejuvenescence of a cell may be mentioned here. The phenomena connected with it are as follows: The proto- plasm of a cell contracts, ex- pels a portion of the water conta
. Botany for high schools and colleges. Botany. 43 BOTANY. the whole of the protoplasm of the mother-cell is used. The former he calls Pree-Cell Formation,&ni. the latter Formation of Cells by Division, of the Mother- Oell, and includes also under the last a part of what has been described above under the head of Fission. It is doubtful, however, whether such a division is of much importance. (6) What has been called the Rejuvenescence of a cell may be mentioned here. The phenomena connected with it are as follows: The proto- plasm of a cell contracts, ex- pels a portion of the water contained in it, and escapes through a slit in its wall; the naked mass becomes for a time a free-swimming zoos- pore, alter which it secretes a wall of cellulose, and begins to grow and form new cells by fission. Cases of this kind occur in (Edogonium, Stigeo- clonium, and many other aquatic Thallophytes. An interesting fact, but proba- bly of no great significance, is that the axis of growth 9f the new cell is perpendicular to that of the old one. While there can be no doubt that this process, as Sachs ,izaconvexula. ^, vertical section '^^^'^'s* ""^"f "^^ regarded of the whole plant; A, hymenium-i.«. the layer morphologically as the for- iiiwhi h the spore-forming sac lie, <S. the tissue „„*:„_, -f „ „„„ poll " tliere of the fungus enveloping the hynienium at its niation ot a new cell, tuere edge q in a cup like manner ; at the base of the can be little question that it tissue S fine threads arise, which grow between . , , i ^ j i. *i r ™ the particles of earth. B, «. small portion of the 33 closely related to the toima- hymenium;«A, sub-hymenlttllnyerof denselyin- tion of zoospores described terwoven filaments (hyphse); a to/, spore-form- , , ,„, mi ing sacs iasci), with tliin filaments (piraphyses) above (p. 40). The ditter- betweeu them. ^ x 20, 5 x Sachs, g^^g jg tij^t in the formation of ordinary zoosp
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1885
