Elementary botany . lium and in the pepper root we have seen that theparts of the flower in each apparent whorl are either of the samenumber as the leaves in a whorl, or some multiple of that num-ber. This is true of a large number of other plants, but it is nottrue of all. A glance at the spring beauty (Claytonia virginiana,and at the anemone (or Isopyrum biternatum, fig. 563) willserve to show that the number of the different members of theflower may vary. The trillium and the dentaria were selectedas being good examples to study first, to make it very clear thatthe members of the flower are
Elementary botany . lium and in the pepper root we have seen that theparts of the flower in each apparent whorl are either of the samenumber as the leaves in a whorl, or some multiple of that num-ber. This is true of a large number of other plants, but it is nottrue of all. A glance at the spring beauty (Claytonia virginiana,and at the anemone (or Isopyrum biternatum, fig. 563) willserve to show that the number of the different members of theflower may vary. The trillium and the dentaria were selectedas being good examples to study first, to make it very clear thatthe members of the flower are fundamentally leaf structures, orrather that they belong to the same series of members as do theleaves of the plant. 649. Synopsis of members of the sporophyte in angiosperms. Higher phase(or modern phase). \ Shoot. Foliage leaves with sporangia.(Sporangia sometimes on shoot.) , Flower. CHAPTER XXXVI. GAMETOPHYTE AND SPOROPHYTE OF 650. Male prothallium of angiosperms.—The first divisionwhich takes place in the nucleus of the pollen grain occurs, inthe case of trillium and many others of the angio-sperms, before the pollen grain is mature. In thecase of some specimens of T. grandiflorum inwhich the pollen was formed during the monthof October of the year before flowering, the divi-Neariy mature sion of the nucleus into two nuclei took placeHum. i he smaller soon after the formation of the four cells from cell is the genera- . .. , , . tiveceii. the mother cell. Ine nucleus divided in the young pollen grain is shown in fig. 385. After this takesplace the wall of the pollen grain becomes stouter, and minutespiny projections are formed. 651. The larger cell is the vegetative cell of the prothallium, while the smaller one, since it later forms the sperm cells, is the generative cell. This generative cell then corresponds to the central cell of the antheridium, and the vegetative cell perhaps co
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