Terms Corresponding to those used in Pteridophytes. Common Terms.
| Terms Corresponding to those used in Pteridophytes. | Common Terms. | |||
|---|---|---|---|---|
| Sporophyte | = | Higher plant. | ||
| Spore-bearing part | = | Stamens and carpels. | ||
| Sporophyte | Microsporophyll | = | Stamen | Anther |
| Filament. | ||||
| Microsporangium | = | Pollen sac, usually two or four. | ||
| Male gametophyte | Microspore at maturity usually of 2 or 3 | = | Pollen grain. | |
| cells {young male prothallium} | ||||
| 1. Large cell (part of antheridium wall?), with | ||||
| its nucleus surrounded by wall of spore | = | Vegetative cell. | ||
| 2. Small cell with nucleus, no wall, floating | ||||
| in protoplasm of large cell is the central | ||||
| cell of antheridium (male sexual organ) | = | Generative cell. | ||
| Mature male prothallium | = | Pollen grain with tube. | ||
| Antheridium cell divided, 2 sperm cells | = | Paternal cells, or generative cells. | ||
| Sporophyte | Macrosporophyll | = | Carpel or simple pistil | Stigma. Style. Ovary. |
| Macrosporangium, covered by 1 or 2 coats | = | Nucellus, covered by 1 or 2 coats = ovule. | ||
| Female gametophyte | Macrospore, cell in end of macrosporangium, does not become free, cavity enlarges | = | Uninuclear state of embryo sac. | |
Macrospore divides into 8 cells to form young female prothallium | = | Embryo sac. | ||
Remnant of archegonium, egg (female sexual organ) | = | Maternal cell, or germ cell. | ||
Growing part of prothallium | = | Two polar nuclei fused, making endosperm nucleus. | ||
Mature female prothallium | = | Endosperm, developed by many divisions of endosperm nucleus. | ||
Young sporophyte surrounded by parts of the gametophyte and new growth of old sporophyte | After fecundation of egg, egg divides to form embryo. Embryo in endosperm (sometimes latter nearly or quite absent) surrounded by coats | = | Seed. | |
Young sporophyte surrounded by remnants of gametophyte and new parts of old sporophyte (remains of endosperm and of nucellus, and ovular coat) = the seed. | ||||
[CHAPTER XXXVII.]
MORPHOLOGY OF THE NUCLEUS AND SIGNIFICANCE
OF GAMETOPHYTE AND SPOROPHYTE.
676. In the development of the spores of the liverworts, mosses, ferns, and their allies, as well as in the development of the microspores of the gymnosperms and angiosperms, we have observed that four spores are formed from a single mother cell. These mother cells are formed as a last division of the fertile tissue (archesporium) of the sporangium. In ordinary cell division the nucleus always divides prior to the division of the cell. In many cases it is directly connected with the laying down of the dividing cell wall.
Fig. 402.
Forming spores in mother cells
(Polypodium vulgare).
Fig. 403.
Spores just mature and wall of mother
cell broken (Asplenium bulbiferum).