File:The structure and development of mosses and ferns (Archegoniatae) (1918) (14598356670).jpg

Identifier: structuredevelop00camp3 (find matches)
Title: The structure and development of mosses and ferns (Archegoniatae)
Year: 1918 (1910s)
Authors: Campbell, Douglas Houghton, 1859-1953
Subjects:
Publisher: New York, Macmillan
Contributing Library: The LuEsther T Mertz Library, the New York Botanical Garden
Digitizing Sponsor: The LuEsther T Mertz Library, the New York Botanical Garden

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
s much greater in diameter than theupper part of the capsule. Sections through the apophysisand seta show a less regular arrangement of the cells than inthe sporiferous part of the capsule, but the general order ofcell-succession is the same, except for the formation of thearchesporium. Almost as soon as the capsule is recognisable,the first indication of the operculum or lid becomes evident.About half-way between the extreme apex of the sporogoniumand the top of the apophysis, a shallow^ depression is noticedextending completely round the capsule and separating thesharply conical apex from the part below. An examination ofa longitudinal section at this point shows that at the point ofseparation the epidermal cells of the opercular portion are muchnarrower than those immediately below. Examining the tis-sues farther in, the archesporium is seen to extend only to apoint opposite the base of the operculum, and the same is trueof the row of large cells where the air-space is formed. If a
Text Appearing After Image:
Fig. 109.—Funaria hygrometrica. A, Longitudinal section of a sporogonium showingthe first differentiation of its parts, X about 96; B, the upper part of the same,X600; r marks the limits of the theca and operculum; C, basal part of the cap-sule of the same, X600. The intercellular spaces are beginning to form; ar,archesporium; col, columella. VI. THE BRYALES 200 similar section is made through an older capsule (Fig. no),it is evident at once that the enlargement takes place mainlybelow the junction of the operculum, and there is also a similarbut less pronounced increase in diameter in the operculum itself;but there is a narrow zone at the junction of the operculum andcapsule, where the epidermal cells increase but little in depth,while those above this point become very much larger and pro-ject beyond them. This narrow zone of cells marks the pointwhere when ripe the operculum becomes detached. The latter,

Note About Images