Flowers, Fruits and LeavesMacmillan, 1886 - 147 páginas |
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Página 3
... shown that in some cases pollen , if placed on the stigma of the same flower , has no more effect than so much inorganic dust ; while , and this is perhaps even more extra- ordinary , in others , the pollen placed on the stigma of the ...
... shown that in some cases pollen , if placed on the stigma of the same flower , has no more effect than so much inorganic dust ; while , and this is perhaps even more extra- ordinary , in others , the pollen placed on the stigma of the ...
Página 5
... shown that plants supplied with insects grow more vigorously than those not so fed . It is very curious that while the glands are so sensitive that even an object weighing only of a grain placed on them is sufficient to cause motion ...
... shown that plants supplied with insects grow more vigorously than those not so fed . It is very curious that while the glands are so sensitive that even an object weighing only of a grain placed on them is sufficient to cause motion ...
Página 6
... shown that if insects have been in some respects modified and adapted with a view to the acquirement of honey and pollen , flowers , on the other hand , owe their scent and honey , their form and colour , to the agency of insects . Thus ...
... shown that if insects have been in some respects modified and adapted with a view to the acquirement of honey and pollen , flowers , on the other hand , owe their scent and honey , their form and colour , to the agency of insects . Thus ...
Página 20
... shown in Fig . 15. The anthers , as they shed their pollen , gradually shrivel up ; while , on the other hand , the pistil increases in length and curves downwards , until it assumes the position shown in Fig . 16 , st , where , as is ...
... shown in Fig . 15. The anthers , as they shed their pollen , gradually shrivel up ; while , on the other hand , the pistil increases in length and curves downwards , until it assumes the position shown in Fig . 16 , st , where , as is ...
Página 32
... shown in the figure , Again , the pollen of the long - styled form is consider- ably smaller than the other , a difference , the import- ance of which is obvious , for each pollen grain has to give rise to a tube which penetrates the ...
... shown in the figure , Again , the pollen of the long - styled form is consider- ably smaller than the other , a difference , the import- ance of which is obvious , for each pollen grain has to give rise to a tube which penetrates the ...
Otras ediciones - Ver todas
Términos y frases comunes
Acacia advantage Agrimony allied animals anthers ants arrangement Beech bees belong branch canina capsule Cardamine carpel CHAP close colour common contrary corolla Crown 8vo curious Darwin Deadnettle dispersion distance Ditto Drosera Drosera rotundifolia edible Epilobium fertilised fertilised by insects flattened fleshy florets flower-head flowers Fritz Müller fruits genera genus Geranium Geranium dissectum Grant Allen ground grow Herb Herb Robert Hibiscus pedunculatus hirta honey hooks Hornbeam Horse Chestnut Illustrations inches insects instance internodes keel Lamium large number Lathyrus leaf-stalk leaflets leaves less light Lime lobed Maple maturity Moreover nearly observed ovary palmate perhaps petals pinnate pistil plants pods pollen Poplar produced protected resemblance ripe ripen scent Seedling seeds Senecio sepals small insects Spanish Chestnut species SQUIRTING CUCUMBER stalk stamens stamens and pistil stem stigma stomata surface Sycamore Thrincia throw trees tube upper Viola canina visits of insects wasp wind wings
Pasajes populares
Página 98 - But the leaves of the herbage at our feet take all kinds of strange shapes, as if to invite us to examine them. Starshaped, heart-shaped, spear-shaped, arrow-shaped, fretted, fringed, cleft, furrowed, serrated, sinuated; in whorls, in tufts, in spires, in wreaths endlessly expressive, deceptive, fantastic, never the same from footstalk to blossom ; they seem perpetually to tempt our watchfulness, and take delight in outstripping our wonder.
Página 117 - Here in the houseless wild, to direct the traveller's journey Over the sea-like, pathless, limitless waste of the desert.
Página 97 - Flowers seem intended for the solace of ordinary humanity : children love them ; quiet, tender, contented ordinary people love them as they grow; luxurious and disorderly people rejoice in them gathered : They are the cottager's treasure ; and in the crowded town, mark, as with a little...
Página 98 - Now. why is this marvellous variety, this inexhaustible treasury of beautiful forms ? Does it result from some innate tendency of each species? Is it intentionally designed to delight the eye of man ? Or has the form and size and texture some reference to the structure and organization, the habits and requirements, of the whole plant...
Página 3 - ... unknown until Mr. Darwin devoted himself to the subject. Our illustrious countryman was the first clearly to perceive that the essential service which insects perform to flowers, consists not only in transferring the pollen from the stamens to the pistil, but in transferring it from the stamens of one flower to the pistil of another. Sprengel had indeed observed in more than one instance that this was the case, but he did not altogether appreciate the importance of the fact. Mr. Darwin, however,...