The Origin of Species by Means of Natural Selection: Or, The Preservation of Favored Races in the Struggle for Life, Volumen2AMS Press, 1972 |
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Página 29
... pistil with short stamens , the other a short pistil with long stamens ; the two having differently sized pollen - grains . With trimorphic plants there are three forms likewise differing in the lengths of their pistils and stamens , in ...
... pistil with short stamens , the other a short pistil with long stamens ; the two having differently sized pollen - grains . With trimorphic plants there are three forms likewise differing in the lengths of their pistils and stamens , in ...
Página 257
... pistil is to allow the pollen - tubes to reach the ovules within the ovarium . The pistil consists of a stigma supported on a style ; but in some Compositæ , the male florets , which of course cannot be fecundated , have a rudimen- tary ...
... pistil is to allow the pollen - tubes to reach the ovules within the ovarium . The pistil consists of a stigma supported on a style ; but in some Compositæ , the male florets , which of course cannot be fecundated , have a rudimen- tary ...
Página 320
... pistil in flowering plants . STIPULES . - Small leafy organs placed at the base of the footstalks of the leaves in many plants . STYLE . The middle portion of the perfect pistil , which rises like a column from the ovary and supports ...
... pistil in flowering plants . STIPULES . - Small leafy organs placed at the base of the footstalks of the leaves in many plants . STYLE . The middle portion of the perfect pistil , which rises like a column from the ovary and supports ...
Contenido
CONTENTS OF VOL | 1 |
CHAPTER X | 48 |
CHAPTER XII | 129 |
Derechos de autor | |
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Términos y frases comunes
accumulated adapted admit adult affinity allied species ancient animals appear Archipelago arctic areas become beds believe birds breeds Cambrian changes characters classification climate closely allied continent crustaceans degree deposited difficulty distant distinct species domestic doubt embryo Europe existing extinct fact faunas fertilised fertility flowers formations formerly forms fossil fresh-water Fritz Müller Gärtner genera genus geological period geological record Glacial period groups of species habits hybrids hybrids produced important individuals inhabitants inherited insects instance intermediate intervals land larvæ less living mammals manner marine Marsupials migration modified descendants mongrels mountains natural selection naturalists nearly occur oceanic islands offspring organisation parent parent-form peculiar perfect pistil plants pollen present probably produced quadrupeds reciprocal crosses regions remains remarked reproductive resemblance rocks rudimentary organs seeds Silurian slight South America species belonging stage stamens sterility structure successive suppose terrestrial tertiary tion variations varieties whilst widely different wings