The structure & development of the mosses and ferns (Archegoniatae) . to the full force of the sun. This latterspecies as well as several others of the same region, Califomica, Targionia ]iypop]iylla, do not die at theend of the rainy season, but become completely dried up, in II MUSCINEyE—HEPA TIC^—MARCHANTIA which condition they remain dormant until the autumn rainsbegin, when they absorb water and begin to grow again at these cases usually only the ends of the branches remainalive, so that each growing tip becomes the beginning of a new plant. T/ie RicciacecB A
The structure & development of the mosses and ferns (Archegoniatae) . to the full force of the sun. This latterspecies as well as several others of the same region, Califomica, Targionia ]iypop]iylla, do not die at theend of the rainy season, but become completely dried up, in II MUSCINEyE—HEPA TIC^—MARCHANTIA which condition they remain dormant until the autumn rainsbegin, when they absorb water and begin to grow again at these cases usually only the ends of the branches remainalive, so that each growing tip becomes the beginning of a new plant. T/ie RicciacecB As a type of the simplest of the Marchantiaceae, we maytake the genus Ricda, represented, according to Schiffner,^ by107 species, distributed over the whole earth. Most of themare small terrestrial plants forming rosettes upon clay soil, orsometimes on drier and more exposed places. A few species, R. fliiitans, are in their sterile condition submersed aquatics,but only fruit when by the evaporation of the water they comein contact with the mud at the Fig. -x.—Riccia glauca (L.). Development of the archegonium, X525. A, Vertical section throut^hthe growing point ; .r, apical cell ; ar, young archegonium ; //, ventral lamellae ; B-F, successivestages in the development of the archegonium, seen in longitudinal section ; G, cross-section ofyoung archegonium (diagrammatic). The dichotomously branched thallus shows a thickenedmidrib, which is traversed upon the dorsal surface by a longi-tudinal furrow which in front becomes very deep. At thebottom of this furrow, at the apex of the thallus, lies the growingpoint. A vertical section through this shows a nearly triangular ^ Schiftner (i), p. 14, 26 MOSSES AND FERNS CHAP. apical cell which lies much nearer the ventral than the dorsalsurface (Fig. 2, x). From this are cut off successively dorsaland ventral segments. Each segment next divides into aninner and an outer cell. From the outer cells of the dorsalsegments the
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Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895
