Lectures on the physiology of plants

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1887 Excerpt: ...the direction of the rows of micellae in starch-grains and thick cell-walls,' &c. I consider that the quotation from my treatise, which had appeared two years previously, difiers from Schwendener's view just cited only in so far that it puts exactly the same ideas more in detail and more clearly, and at the same time directly contradicts Schwendener's older views (1877) on the relation of growth and cell-division. DEPENDENCE OF DI VISION UPON THE FORM OF THE CELL. the individual cells of which grow independently after each division; as in the genera Chlorococcus, Merismopedia, Telraspora, Glceocapsa, and many others. In more highly developed plants similar processes take place in the mother-cells of spores and pollen grains. In these cases the fact is particularly clear, that the mode in which the cell-divisions follow one another depends by no means on the physiological or morphological nature of the cells, but upon their mode of growth and external form--especially upon the latter. Fig. 267, for example, shows six different forms of cell-division in the pollen mother-cells of one and the same plant, the Orchid Neollia nidus-avis. In A the pollen mother-cell had approximately the form of a circular disc, which, by means of two divisions at right angles to one another, is cut lip into four quadrants. It is to be noticed, however, that the two vertical division-walls in Fig. A do not exactly meet one another, so that a small piece of the horizontal division-wall remains intercalated between the points where they join it: this intercalated piece of the previous division-wall appears like a breaking of it, and we meet with such interruptions of the walls very generally in the division oT tissue-cells, a point on which I lay some stress, because in the more...