. A handbook of cryptogamic botany. Cryptogams. CHAR ACEJE 177 thallium or ' pro-embryo ' which proceeds from the germinating oosperm. No mode of vegetative propagation is known in the other genera. The sexual reproductive organs of the Characese, the male antherids and the female archegones, are visible to the naked eye as minute orange- red globes and elliptical green bodies springing from the nodes in the axils of leaves or bracts. The antherids are glo- bular bodies, of a bright red colour when mature, from ^ to I mm. in dia- meter, morphologically the terminal cell of a leaf or lateral le
. A handbook of cryptogamic botany. Cryptogams. CHAR ACEJE 177 thallium or ' pro-embryo ' which proceeds from the germinating oosperm. No mode of vegetative propagation is known in the other genera. The sexual reproductive organs of the Characese, the male antherids and the female archegones, are visible to the naked eye as minute orange- red globes and elliptical green bodies springing from the nodes in the axils of leaves or bracts. The antherids are glo- bular bodies, of a bright red colour when mature, from ^ to I mm. in dia- meter, morphologically the terminal cell of a leaf or lateral leaflet. The moderately thick wall of the antherid is made up of eight flat disc-shaped cells called shields, four of which, situated round the distal pole of the ball, are tri- angular, while the four situated round the base are four-sided. On their inner face there lies a layer of chlorophyll- grains, which eventually turn red, while the outer face is clear and trans- parent ; the walls of these cells are folded in- wards at the edge where they meet. From the centre of the inner face of each shield a cylin- drical cell, termed a handle or manubrium, projects inwards nearly to the centre of the globe. The antherid is supported on a short flask-shaped/«^zce/-«//, which also projects into the interior between the four, lower four-sided shields. At the free end of each'of the eight manubria is a roundish hyaline cell, the head-cell or. capitulum. These twenty-five cells—viz. the eight shields, eight manubria, eight capituia, and the pedicel-cell—constitute the. Fig. 163.—Nitella Jiexilis Ag. A^ nearly ripe antherid sub- tended by two bracts showing direction of protoplasm-curients, and neutral zone, i. .5, manubrium, with capitulum, secondary capituia, and whip-like filaments. C—F, antheridial filaments, showing formation of antherozoids. G, antherozoids (C—6^ x 550). (After Sachs.). Please note that these images are extracted from scanned page images that may have been
Size: 1275px × 1960px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublisherlondonnewyorklongm
