A Manual of Botany: Anatomical and Physiological for the Use of Students

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Blackwood, 1874 - Botany - 614 pages
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Page 387 - When, therefore, the floral organs are called modified or metamorphosed leaves, it is not to be supposed that a petal has ever actually been a green leaf, and has subsequently assumed a more delicate texture and hue, or that stamens and pistils have previously existed in the state of foliage ; but only that what is fundamentally one and the same organ develops, in the progressive evolution of the plant, under each or any of these various forms. When the individual organ has developed, its destiny...
Page 582 - Passion-flowers, which show the revolving so well in a sultry day, we may see, with wonder, that when a tendril, sweeping horizontally, comes round so that its base nears the parent stem rising above it, it stops short, rises stiffly upright, moves on in this position until it passes by the stem, then rapidly comes down again to the horizontal position, and moves on so until it again approaches and again avoids the impending obstacle ! 29.
Page 448 - ... of membrane to which the caudicle adheres is endowed with a remarkable power of contraction, which causes the pollinium to sweep through an angle of about ninety degrees, always in one direction, viz., towards the apex of the proboscis or pencil, in the course of thirty seconds on an average.
Page 442 - With this tentacle she collects the pollen, thrusts it into the stigmatic tube, and having thus fertilized the flower, she consigns a few eggs to the young fruit, the seeds of which her larvae feed on.
Page 581 - ... with their petioles, of flower-peduncles, perhaps also of branches and stipules. The species of tendril bearers described belong to ten natural families. Species of Bignonia and some others taken together, afford connecting links between twiners, leaf-climbers, tendril-bearers, and root climbers. Some little time after the stem of Bignonia Tweedyana has twined round an upright stick, and is securely fastened to it by the clasping petioles and tendrils, it emits at the base of its leaves aerial...
Page 197 - ... bundles ; or the increased size of the coming leaf-bud will snap them ; or, if these causes are not in operation, a gust of wind, a heavy shower, or even the simple weight of the lamina, will be enough to disrupt the small connections and send the suicidal member to its grave. Such is the history of the fall of the leaf. We have found that it is not an accidental occurrence, arising simply from the...
Page 450 - ... other of these small openings it cannot fail to get a dab of pollen upon its head, as it brushes against the film with which the surface is varnished. Flying to the next blossom and entering as before, as the insect makes its way onward, it can hardly fail to rub the pollen-covered top of its head against the large stigma which forms the roof of the passage.
Page i - BROWN. The Ethics of George Eliot's Works. By JOHN CROMBIE BROWN. Fourth Edition. Crown 8vo, 2s. 6d. BROWN. A Manual of Botany, Anatomical and Physiological.
Page 472 - Both these natural orders agree in having the calyx adherent to the ovary, and in their fruits being austerely sour before ripening. It would even seem, from the fruits of the persimmon, the sorb, and the medlar, that the more austere a fruit is, the more it is capable of bletting regularly.
Page 441 - I have also found that the visits of bees are necessary for the fertilisation of some kinds of clover; for instance, twenty heads of Dutch clover (Trifolium repens) yielded 2,290 seeds, but twenty other heads protected from bees produced not one.

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