The structure & development of the mosses and ferns (Archegoniatae) . s of a large number ofLiverworts belonging to all theprincipal groups have been examinedby me, and invariably the presenceof a definite cell wall can be demon-strated at all stages. Many of the foHose Hepaticaeshow much greater regularity in theearly divisions of the embryo, andin the establishment of the arche-sporium and the arrangement of itscells. This is especially marked inFnillania? Here, after the upperFig « Boianderi (Aust.). ^ ^ embryo has divided into Longitudinal section of a sporo- i:-^-<- ^- ^^?^ ^^l^ij
The structure & development of the mosses and ferns (Archegoniatae) . s of a large number ofLiverworts belonging to all theprincipal groups have been examinedby me, and invariably the presenceof a definite cell wall can be demon-strated at all stages. Many of the foHose Hepaticaeshow much greater regularity in theearly divisions of the embryo, andin the establishment of the arche-sporium and the arrangement of itscells. This is especially marked inFnillania? Here, after the upperFig « Boianderi (Aust.). ^ ^ embryo has divided into Longitudinal section of a sporo- i:-^-<- ^- ^^?^ ^^l^ij^ j ^ gonium after the final division of the thrCC tlcrS of Cclls, thcSe UudcrgO sporogenous cells, X 85. , , , ,. . , the usual quadrant divisions, andthe four terminal cells only, formthe capsule, in which the archesporium is established bythe first periclinal walls (Fig. 50). The divisions in thearchesporium are also extremely regular, so that the sporesand elaters form regularly alternating vertical rows. In1 Le Clerc du Sablon (3). - Leitgeb (2), vol. IV THE JUNGERMANNIACE/E 107 Frullania the lower cell of the embryo, instead of remainingundivided, or forming simply a row of cells, divides repeatedly,and the cells grow out into papillae, so that it probably isfunctional as an absorbent organ, like the foot of the Antho-ceroteae. Radula ^ and Jimgerma7inia, while more regular inthe divisions than Porella, still arc less so than Frullania, andin these more than the upper tier of cells take part in thegrowth of the capsule. The degree to which the seta and footare developed varies. In Porella there is not a distinctly markedfoot, the lower part of the seta being simply somewhat enlarged,but in others, like Jungeruiannia bicuspidata, there is a largeheart-shaped foot, very distinct from the seta. In Porella theseta is short, projecting but little beyond the perianth ; but inothers it may reach a length of several centimetres. The development of the perianth is quite inde
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Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895
