 | Charles Darwin - 1861 - Страниц: 470
...visits of bees are necessary for the fertilisation of some kinds of clover ; for instance, 20*heads of Dutch clover (Trifolium repens) yielded 2290 seeds,...red clover, as other bees cannot reach the nectar. Hence I have very little doubt, that if the whole fanus of humble-bees became extinct or very rare... | |
 | 1867 - Страниц: 378
...heads of red clover (trifolium pretense) produced 2,700 seeds, but the some number of protected hends produced not a single seed. Humble-bees alone visit...cannot reach the nectar. It has been suggested that mothsmay serve to fertilize the clovers ; bat I doubt this in the case of the red clover, from' their... | |
 | Charles Darwin - 1864 - Страниц: 472
...which I have lately tried, I have found that the visits of bees are necessary for the fertilisation of some kinds of clover ; for instance, 20 heads of...red clover, as other bees cannot reach the nectar. Hence I have very little doubt, that if the whole genus of humble-bees became extinct or very rare... | |
 | Charles Darwin - 1866 - Страниц: 668
...heads protected from bees produced not one. Again, 100 heads of red clover (T. pratense) produced 2,700 seeds, but the same number of protected heads produced...reach the nectar. It has been suggested that moths may serve to fertilise the clovers ; but I doubt this in the case of the red clover, from their weight... | |
 | Robert Bird - 1870 - Страниц: 262
...2290 seeds, but 20 other heads protected from bees produced not one. Again, 100 heads of red clover produced 2700 seeds, but the same number of protected...reach the nectar. It has been suggested that moths may serve to fertilize the clovers ; but I doubt this in the case of the red clover, from their weight... | |
 | Charles Darwin - 1870 - Страниц: 468
...from bees produced not one ; again, 100 heads of red clover (T. pratense) produced 2700 seeds, out the same number of protected heads produced not a...red clover, as other bees cannot reach the nectar. Hence I Jiave very little doubt, that if the whole genus of humble-bees became extinct or very rare... | |
 | John Tillotson - 1870 - Страниц: 1154
...were flowers of that sort ? or if the flowers were first, how did they multiply without the insects ? Humblebees alone visit red clover, as other bees cannot reach the nectar ; and they are almost indispensable to the fertilisation of the heartsease, a flower not visited by... | |
 | 1874 - Страниц: 586
...almost indispensable to the fertilization of th.e heart's ease, for these Bees do not visit this flower. HumbleBees alone visit red clover as other Bees cannot reach the nectar. In a word — no Bees, no seed ; no seed, no increase of the flower. The more visits from Bees, the... | |
 | Charles Darwin - 1875 - Страниц: 504
...heads protected from bees produced not one. Again, ICO heads of red clover (T. pretense) produced 2,700 seeds, but the same number of protected heads produced...reach the nectar. It has been suggested that moths may fertilise the clovers ; but I doubt whether they could do so in the case of the red clover, from their... | |
 | William Swinton, George Rhett Cathcart - 1880 - Страниц: 364
...red clover produced 2700 seeds, but the same number of protected heads produced not a single seed. 4. Humble-bees alone visit red clover, as other bees cannot reach the nectar. Hence I have very little doubt, that if the whole genus of humble-bees became extinct or very rare... | |
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Hence we may infer as highly probable that, if the whole genus of humble-bees became extinct or very rare in England, the heartsease and red clover would become very rare, or wholly disappear. 
