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Plant reproductive morphology is concerned with the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show a correspondingly great diversity in methods of reproduction.〔 Plants that are not flowering plants (green algae, mosses, liverworts, hornworts, ferns and gymnosperms such as conifers) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how the sperm from one plant fertilizes the ovum of another, depends on the reproductive morphology, and is the single most important determinant of the genetic structure of nonclonal plant populations. Christian Konrad Sprengel (1793) studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions. Charles Darwin's theories of natural selection utilized this work to build his theory of evolution, which includes analysis of the coevolution of flowers and their insect pollinators. == Use of sexual terminology == Plants have a complex lifecycle involving alternation of generations. One generation, the sporophyte, gives rise to the next generation via spores. Spores may come in different sizes (microspores and megaspores), but strictly speaking, spores and sporophytes are neither male nor female. The alternate generation, the gametophyte, produces eggs and sperm. A gametophyte can be either female (producing eggs), male (producing sperm) or hermaphrodite (monoicous, producing both eggs and sperm). In groups like liverworts, mosses and hornworts, the dominant generation is the sexual gametophyte. In ferns and seed plants (including cycads, conifers, flowering plants, etc.) the sporophyte is by far the most dominant generation. The obvious visible plant, whether a small herb or a large tree, is the sporophyte, and the gametophyte is very small. In seed plants, the female gametophyte, and the spores that give rise to it, are hidden within the sporophyte and are entirely dependent on it for nutrition. The male gametophyte consists of a few cells within a pollen grain. The sporophyte of a flowering plant is often described using sexual terms (e.g. "female" or "male") . For example, a sporophyte that produces spores that give rise only to male gametophytes may be described as "male", even though the sporophyte itself is asexual, producing only spores. Similarly, flowers produced by the sporophyte may be described as "unisexual" or "bisexual", meaning that they give rise to either one sex of gametophyte or both sexes of gametophyte.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Plant reproductive morphology」の詳細全文を読む スポンサード リンク
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