Elementary Notes on the Reproduction of Angiosperms (Classic Reprint)
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| Stand: | 2015-08-04 03:50:33 |
Produktbeschreibung
Excerpt from Elementary Notes on the Reproduction of Angiosperms Reproduction of Angiosperms: The Flower. Reproduction: Apart from lomatic organisation of the leaf. Hem, and root, constituting the working mechanism of the life of the individual. It is necessary to conrider the mechanism for maintaining the existence of the ratt, as the ind dust-wear out, owing to the Imperfection of metabolic mechanism, and die. The subject also includes The possibility of the improvement of the race, as progression in h*u (a) Dispersal to new stations, as progression in tpa*t. Dispersal impi´es enormous Matfagt, In the chance of finding new -ui.or and further wastage in competition for unoccupied ground, with individuals of the same race, or dinerent forms of organism. Ikyond the maintenance of its own existence and growth, the entire working life of the organism may be spent in compensating wastage. If this is not done the race dies out. Races exist on the a Law of the Minimum*; so that output of reproductive units of different categories may be taken as the price of existence (Waifagt- plication can be effected quite as efficiently by * Vrgttatrvt Pr fagatm Kconomy in such wastage is the criterion of higher organism; the mechanism of repioduction of the Flowering-plant being so far the highest expression of iuccc* il; lant-organum Angioapcrma: In Flowering Plants of nigher order the whole of the reproductive processes are included w-lthin the mechanism of special shoots distinguished as Flown, attaining their limit in the production of seeds, from which Individuals of type similar to the parent organism can be produced, as a fact of general experience. The organization of the flower includes a series of extremely complex phenomena, only to be understood by tracing its evolutionary progression from earlier stages of plant-life. The analysis of the mechanism of flowers is the most important part of iiotany from the standpoint of Reproduction, rather than from that of Systematy; the latter follows as a consequence. Anciont History: Vague ideas of * sex * in plants go back to remote epochs (cf. Date-Palm). Linnaeus (XVIII century) regarded a flower as a sexual mechanism ; stamens male, and ´pistm * female; hence such terms as ovary, htrmapkrodiU, etc.. are still retained in metaphorical sense as convenient conventions. Phenomena analogous with ttx in animals are microscopic in dimensions, and wholly enclosed in the tissues; the reproductive mechanism is more complex, and in many respects more advanced, than in any animaL General Idoa of a Flower. A shoot-system, with characters different from the normal photosynthetic shoot, set apart to perform the whole of the reproductive functions, sexual and asexual, culminating in the liberation of seeds and including the essential mechanism of:- (l) Pollination, (a) Fertilisation, (3) Dispersal, as also the developmental history of:- (1) Spore*, (a) Gam® to®, (3) Th® Embryo respecuvel), and the mode of nutrition of these respective units. Doflnition: ´An axis bearing sporophylls*; with emendations,- (1) A special axis, 1. e. a branch (= strobihis). (a) Sporophylls, as spore-producing leaf-membera, bearing spores of a kinds. Micro- and Mega-, as the ´ hermaphrodite * condition. (3) With accessory protective members (perianth), and arrangement in definite sequence (= anthostrobilus). (^) The ports co-ordinated by growth-factors, and ame-factors, to constitute a floral mechanism; the first object of which is to secure nut pollination, i. e. pollinated from another indiv
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