The structure & development of the mosses and ferns (Archegoniatae) . successful cross-sections of the very young prothalliumwere made, the archegonium mother cell was decidedly triangu-lar, showing that it was formed by three intersecting walls, asin Isoetes. It divides into an outer and inner cell, the latter,as in Isoetes^ giving rise at once to egg and canal cells, withoutthe formation of a basal cell. Up to this point the exospore remains intact ; the central ^ Prantl (4), p. 427. 384 MOSSES AND FERNS CHAP. cell of the archegonium is only separated from the sporecavity by a single layer o
The structure & development of the mosses and ferns (Archegoniatae) . successful cross-sections of the very young prothalliumwere made, the archegonium mother cell was decidedly triangu-lar, showing that it was formed by three intersecting walls, asin Isoetes. It divides into an outer and inner cell, the latter,as in Isoetes^ giving rise at once to egg and canal cells, withoutthe formation of a basal cell. Up to this point the exospore remains intact ; the central ^ Prantl (4), p. 427. 384 MOSSES AND FERNS CHAP. cell of the archegonium is only separated from the sporecavity by a single layer of cells, and the young prothalliumagrees closely with Prantls account of the similar stage ofSalvinia (Fig. 198, A, B). Berggrens ^ figures of A. Caro-lihiana^ at a stage presumably the same, are too diagrammaticto allow of a satisfactory comparison. Shortly after the first division in the archegonium a rapidincrease takes place in the size of all the cells of the prothallium,by which it expands and ruptures the exospore, which breaksopen by three lobes at the ..ep
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Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895
