Text-book of botany, morphological and physiological . empt has also sometimesbeen successful, in theformation of tissue-cells,to separate the twodaughter-cells completely by contractile reagents, before a division-wall has arisen be-tween them : as also in the first divisions of the young antheridium of Gharaceae(Fig. 43, B). But usually, especially in the formation of the tissues of the higherplants, the appearance of the division-wall follows so rapidly after that of the twonuclei, that it is seldom possible to catch the exact moment when the deriva-tive cells are already parted, but are no
Text-book of botany, morphological and physiological . empt has also sometimesbeen successful, in theformation of tissue-cells,to separate the twodaughter-cells completely by contractile reagents, before a division-wall has arisen be-tween them : as also in the first divisions of the young antheridium of Gharaceae(Fig. 43, B). But usually, especially in the formation of the tissues of the higherplants, the appearance of the division-wall follows so rapidly after that of the twonuclei, that it is seldom possible to catch the exact moment when the deriva-tive cells are already parted, but are not yet separated by a partition-wall. In theexamination of-the Punctum i>egetationis of roots and stems, one sees at a glancehundreds of cells which are in process of division at the same time ; and yet it isseldom possible to see the condition in question. This however shows at the sametime that the partition-wall always arises in these cases simultaneously over thewhole surface ; if it grew from without inwards, this would actually be seen, since. Fig. 13.—Formation of tlie anthericlium n{Nitella flexilis (cf. Book II). ^ The firm connexion of the two daughter-cells before the formation of the partition-walloccurs also in a different manner, in Oedogonium (Hofmeister, pp. 84 and 162). Thepreliminary indication of the partition-wall by the appearance of a disc of granules in the boundaryplane is not universal, as is shown in the formation of the pollen of Funkia and of the spores ofFunaria. (Hofmeister, /. c. Fig. 20.) FORMATION OF CELLS. 17
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
