On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeEaston Press, 1976 - 470 páginas |
Dentro del libro
Resultados 1-3 de 13
Página 71
... stamens and pistils placed , in relation to the size and habits of the particular insects which visited them , so as ... stamens producing a rather small quantity of pollen , and a rudimentary pistil : other holly - trees bear only ...
... stamens and pistils placed , in relation to the size and habits of the particular insects which visited them , so as ... stamens producing a rather small quantity of pollen , and a rudimentary pistil : other holly - trees bear only ...
Página 177
... stamens which stand opposite to the sepals are all aborted , a sixth stamen stand- ing opposite to a petal being alone developed ; and this stamen is not present in the ordinary flowers of these species ; the style is aborted ; and the ...
... stamens which stand opposite to the sepals are all aborted , a sixth stamen stand- ing opposite to a petal being alone developed ; and this stamen is not present in the ordinary flowers of these species ; the style is aborted ; and the ...
Página 456
... STAMENS . — The male organs of flowering plants , standing in a circle within the petals . They usually consist of a filament and an anther , the anther being the essential part in which the pollen , or fecundating dust , is formed ...
... STAMENS . — The male organs of flowering plants , standing in a circle within the petals . They usually consist of a filament and an anther , the anther being the essential part in which the pollen , or fecundating dust , is formed ...
Contenido
VARIATION UNDER NATURE | 30 |
STRUGGLE FOR EXISTENCE | 45 |
NATURAL SELECTION | 59 |
Derechos de autor | |
Otras 13 secciones no mostradas
Otras ediciones - Ver todas
Términos y frases comunes
accumulated adapted admit affinities allied species America ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common progenitor continuous crossed crustaceans degree developed difficulty distinct species divergence doubt effects eggs embryo existing exterminated extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period gradations greater number groups of species habits Hence hybrids hybrids produced important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner marsupials migration modified descendants natural selection naturalists nearly nest occasionally offspring organisation organs Origin of Species parent peculiar perfect pigeons pistil plants pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds slight South America stamens sterility structure struggle successive supposed swimbladder theory variability variations varieties vary whilst whole wings young