. Text-book of botany, morphological and physiological. Botany. 36° MUSCINEJE. segments; the lower parts together with the ventral segment are employed in the formation of the perigynium. The further development of the archegonia and antheridia has already been described. In the species examined by Hofmeister the fertilised oosphere is first divided by a transverse septum, i. e. at right angles to the axis of the archegonium. Only the upper of the two cells, the one towards the neck of the archegonium, becomes further divided, and it gives rise to four apical cells arranged as octants of a sph
. Text-book of botany, morphological and physiological. Botany. 36° MUSCINEJE. segments; the lower parts together with the ventral segment are employed in the formation of the perigynium. The further development of the archegonia and antheridia has already been described. In the species examined by Hofmeister the fertilised oosphere is first divided by a transverse septum, i. e. at right angles to the axis of the archegonium. Only the upper of the two cells, the one towards the neck of the archegonium, becomes further divided, and it gives rise to four apical cells arranged as octants of a sphere, as described above. The basal portion of the growing archegonium becomes swollen out and penetrates down into the tissue of the stem, being nourished and firmly enclosed by it (the vaginula). As soon as the young sporogonium consists of a number of cells, its wall becomes differ- entiated from the inner tissue which is to form the spores and elaters. In Frullatzia it is a single circular disc of cells lying trans- versely beneath the dome of the young sporo- gonium from which the vertical elaters, and by further divisions, the mother-cells of the spores arise, a process which reminds one of what occurs in Sphagnum. In most true Jungermannieae there is, on the other hand, a column of tissue consisting of vertical rows of cells (surrounded by the wall of the sporo- gonium consisting of two layers), out of which the elaters and spores are formed. The elaters lie, in this case, horizontally, and radiate from the ideal longitudinal axis to the wall of the sporogoninm (Fig. 246). In Pellia the inner fertile tissue forms, after the differentiation of the wall of the sporogonium, a hemisphere, from the cells of which arise the spores and the elaters radiating from below upwards, in a similar manner to what occurs in the Mar- chantieae. By a rapid extension of the hitherto short seta, the calyptra is ruptured at the apex, and the globular sporogonium with the already ripe spores i
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1882
