. The different forms of flowers on plants of the same species. Plants; Fertilization of plants; Heterostylism. Long-styled Short-styled female. female. Rhamnus catharticus. length of this organ. Both the petals and sepals are decidedly smaller in the females than in the males; and the sepals do not turn downwards, as do those of the male flowers when mature. All the flowers on the same male or same female bush, though subject to some variability, belong to the same sub-form; and as my son never experienced any difficulty in decid- ing under which class a plant ought to be included, he believe
. The different forms of flowers on plants of the same species. Plants; Fertilization of plants; Heterostylism. Long-styled Short-styled female. female. Rhamnus catharticus. length of this organ. Both the petals and sepals are decidedly smaller in the females than in the males; and the sepals do not turn downwards, as do those of the male flowers when mature. All the flowers on the same male or same female bush, though subject to some variability, belong to the same sub-form; and as my son never experienced any difficulty in decid- ing under which class a plant ought to be included, he believes that the two sub-forms of the same sex do not graduate into one another. I can form no satisfactory theory how the four forms of this plant originated. Bhamnus lanceolatus exists in the United States, as I am informed by Professor Asa Gray, under two hermaphrodite forms. In the one, which may be called the short-styled, the flowers are sub-solitary, and in- clude a pistil about two-thirds or only half as long as that in the other form; it has also shorter stigmas. The stamens are of equal length in the two forms ; but the anthers of the short-styled contain rather less pollen, as far as I could judge from a few dried flowers. My 30. 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 Darwin, Charles, 1809-1882. New York, D. Appleton and company
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectplants, bookyear1897
