The structure & development of the mosses and ferns (Archegoniatae) . K .2 I (/: in. X ii ?J i k2 I O tr . 0 00 vo a> •^ X -5 are formed in their walls. The protoplasm is mainly used upin the formation of the spiral and ring-shaped thickenings uponthe inner surface of the wall, so characteristic of these cells 164 MOSSES AND FERNS chap. (Fig. 78, D). The chlorophyll cells are sometimes so crowdedand overarched by the hyaline ones that they are scarcelyperceptible, and of course in such leaves the green colour isvery faint. Cross-sections of the leaves show a characteristicbeaded appearance,
The structure & development of the mosses and ferns (Archegoniatae) . K .2 I (/: in. X ii ?J i k2 I O tr . 0 00 vo a> •^ X -5 are formed in their walls. The protoplasm is mainly used upin the formation of the spiral and ring-shaped thickenings uponthe inner surface of the wall, so characteristic of these cells 164 MOSSES AND FERNS chap. (Fig. 78, D). The chlorophyll cells are sometimes so crowdedand overarched by the hyaline ones that they are scarcelyperceptible, and of course in such leaves the green colour isvery faint. Cross-sections of the leaves show a characteristicbeaded appearance, the large swollen hyaline cells regularlyalternating with the small wedge-shaped sections of the greencells (Fig. 78, E). Russow^ has shown that the leaves of thesporogonial branch retain more or less their primitive character,and the division into the two sorts of cells of the normal leavesis much less marked. He connects this with the necessity forgreater assimilative activity in these leaves for the support ofthe growing sporogonium. From his account too it seems thatthe
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Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895
