. Text-book of botany, morphological and physiological. Botany. EQUISETINEjE. 393 for a few days), show, when sown in water or on damp soil, the preparatory phases of germination after a few hours. In the course of some days the pro- thallium becomes developed into a multicellular plate, the further growth of which then proceeds very slowly. The spore, which contains a nucleus and chlorophyll- granules, increases in size as soon as germination commences, becomes pear-shaped, and divides into two cells, one of which is smaller with scarcely any except colourless contents, and soon developes int
. Text-book of botany, morphological and physiological. Botany. EQUISETINEjE. 393 for a few days), show, when sown in water or on damp soil, the preparatory phases of germination after a few hours. In the course of some days the pro- thallium becomes developed into a multicellular plate, the further growth of which then proceeds very slowly. The spore, which contains a nucleus and chlorophyll- granules, increases in size as soon as germination commences, becomes pear-shaped, and divides into two cells, one of which is smaller with scarcely any except colourless contents, and soon developes into a long hyaline root-hair (Fig. 274, /, II, III, w), while the anterior and larger cell includes all the chloro- phyll-granules of the spore which multiply by division. This cell produces by further divisions the primary plate of the prothallium, which in- creases by apical growth and soon branches (III- VI). The process of multiplication of the cells is therefore apparently extremely irregular; even the very first divisions vary; sometimes the first wall in the primary apical cell which contains chlorophyll is but little inclined with respect to the longitudinal axis of the young plant (in E, Telmateia it sometimes coincides with it); in other cases, on the contrary, this cell developes into a longish tube, the apical part of which is cut off by a transverse septum (occasionally in E. arvense). The further growth is brought about by one or more apical cells dividing by trans- verse septa, and longitudinal walls are subse- quently formed in the segments in an order very difficult to determine. Ramification takes place by the bulging out of lateral cells, which then continue their growth in a similar manner. The chlorophyll-granules in the cells also increase con- tinuously by division. The young prothallia are, in E. Telmateia, usually narrow and ligulate, and consist of but a single layer of cells. The older prothallia are, both in this and in other species, branched in an ir
Size: 953px × 2622px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1882
