File:A textbook of botany for colleges and universities (1910) (20117548344).jpg

Title: A textbook of botany for colleges and universities ..
Identifier: cu31924001221609 (find matches)
Year: 1910 (1910s)
Authors: Coulter, John Merle, 1851-1928; Barnes, Charles Reid, 1858-1910, joint author; Cowles, Henry Chandler, 1869- joint author
Subjects: Botany
Publisher: New York, Cincinnati (etc) American book company
Contributing Library: Cornell University Library
Digitizing Sponsor: MSN

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:
MORPHOLOGY that the microsporangia have advanced very little beyond the fern level. Ovulate structures. — The megasporangiate structures, however, have advanced very far beyond the fern level, and are very peculiar (fig. 431). The seeds terminate long and slender stalks, which are packed among interseminal scales that are also stalked structures. The stalked seeds and interseminal scales are arranged so as to form an ovoid, fruitlike body, with a mosaic surface composed of the flaring tops of the interseminal scales, wedged between which the micropylar tubes of the seeds protrude. If this structure be compared with the seed-bearing structures of the Cycadofilicales, especially those in which the seeds terminate the naked branches of a pinna, it will be observed that if these branches be reduced to a single axis, the condition in Ben- nettitales is obtained. The inter- seminal scales are probably sterile megasporophylls; and all the megasporophylls, leaflike and spreading in Cycadofilicales, are compacted into a strobilus in Bennettitales. Fig. 4=9-— Strobilus of a species of Seeds.—The structure of the Cycadcoidca, in which the seeds are mature, seeds has been obtained from seC- and showing the shoulder (a) which bore the ^^ ^^.j^j^j^ ^j^^^^ ^ ^^^^^ , stamens. — After Wieland. . ^ ' suggesting a rudiment of the in- vesting and husklike cupule of some of the Cycadofilicales; a two or three layered testa ; and a large dicotyledonous embryo completely filling the seed (fig. 432). This embryo is unlike that of any living gymnosperm, in that in developing it destroys all of the endosperm (see p. 202).
Text Appearing After Image:
'

Note About Images