The structure & development of the mosses and ferns (Archegoniatae) . s to them. After this transverse and longitudinalwalls succeed with such regularity that the limits of the primarysegments remain perfectly evident until the antheridium isnearly full grown. The central cells in the fresh antheridium are stronglyrefringent, and in stained sections show a much more granularconsistence than the outer ones. The nucleus, as in othercases studied, uses its nucleolus before the formation of thespermatozoids begins. The latter in their structure andd^elopment correspond with those of Sphagnum, but
The structure & development of the mosses and ferns (Archegoniatae) . s to them. After this transverse and longitudinalwalls succeed with such regularity that the limits of the primarysegments remain perfectly evident until the antheridium isnearly full grown. The central cells in the fresh antheridium are stronglyrefringent, and in stained sections show a much more granularconsistence than the outer ones. The nucleus, as in othercases studied, uses its nucleolus before the formation of thespermatozoids begins. The latter in their structure andd^elopment correspond with those of Sphagnum, but owing totheir smaller size are not favourable for studying the minutedetails of development. In the peripheral cells are numerous chloroj^lasts whichlie close to the inner wall of the cell in the ripe antheridium. igo MOSSES AND FERNS CHAP. As the antheridium ripens, these gradually assume a brightorange-red colour. The development of the stalk varies indifferent cases. Sometimes it consists of a row of severalcells, sometimes the antheridium is almost sessile. The. Fig. 91.—Futiaria hygrometrica (Sibth.). A, Antheridium that has just discharged the mass ofsperm cells (B), X300; C, spermatozoids, X1300; D, paraphjsis, X300; E, male flower ofAtrichuvi iindulatujn, X6 lowermost segments of the apical cell help to form the upperpart of the stalk, and sometimes the two lowest seem totake no part in the formation of the sperm cells. There is noabsolute uniformity in the cell divisions of the stalk, which VII THE BRYINE^E 191 varies in the arrangement of the cells in different individuals inthe same inflorescence. If ripe antheridia are placed in water, they open within afew minutes. The peripheral cells become much distended,especially the terminal ones ; and the chromatophores beingentirely confined to the inner part of the cells, the antheridiumseems to be surrounded by a layer of perfectly hyaline dehiscence takes place at the summit between the terminalcells, which a
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