. Botany, with agricultural applications. Botany. FEMALE GAMETOPHYTE 449 sporangium as in Selaginella, but a new feature of the Cycads is that the megasporangium does not open to allow the megaspore to be exposed, and therefore the female gametophyte remains permanently enclosed in the sporangium. The developing female gametophyte uses most of the nucellus for food and thereby makes room for itself. When the gametophyte is mature the. Fig. 399. â Section through a Cycad ovule containing a mature gameto- phyte. /, female gametophyte with two archegonia (a) shown; m, micro- spores developing tub
Image details
Contributor:
The Book Worm / Alamy Stock PhotoImage ID:
RDWCKCFile size:
7.1 MB (396.2 KB Compressed download)Releases:
Model - no | Property - noDo I need a release?Dimensions:
1382 x 1808 px | 23.4 x 30.6 cm | 9.2 x 12.1 inches | 150dpiMore information:
This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright. Alamy charges you a fee for access to the high resolution copy of the image.
This image could have imperfections as it’s either historical or reportage.
. Botany, with agricultural applications. Botany. FEMALE GAMETOPHYTE 449 sporangium as in Selaginella, but a new feature of the Cycads is that the megasporangium does not open to allow the megaspore to be exposed, and therefore the female gametophyte remains permanently enclosed in the sporangium. The developing female gametophyte uses most of the nucellus for food and thereby makes room for itself. When the gametophyte is mature the. Fig. 399. â Section through a Cycad ovule containing a mature gameto- phyte. /, female gametophyte with two archegonia (a) shown; m, micro- spores developing tubes, and male gametophytes; n, nucellus; i, integument; â p, pollen chamber into which the micropyle shown just above opens. Re- drawn from Webber. nucellus is so nearly used up that it is reduced to a thin layer, except at the micropylar end where a beak-like portion remains. A female gametophyte when fully formed consists of a large num- ber of cells, most of which form a nutritive tissue for the devel- oping sporophyte and are therefore spoken of as endosperm, although the endosperm of Cycads is not the same in origin as the endosperm of Angiosperms. The archegonia, usually several in. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Martin, John N. (John Nathan), b. 1875. New York, John Wiley & sons, inc. ; [etc. , etc. ]