 I have also found that the visits of bees are necessary for the fertilization of some kinds of clover; for instance, 20 heads of Dutch clover (Trifolium repens) yielded 2,290 seeds, but 20 other heads protected from bees produced not one.  The Physical Basis of Society - الصفحة 58بواسطة Carl Kelsey - 1916 - عدد الصفحات: 406عرض كامل - لمحة عن هذا الكتاب
 | 1921 - عدد الصفحات: 460
...account which reads as follows (Darwin 1, p. 71) :* "From experiments wfhich I have lately tried, I have found that the visits of bees are necessary for the fertilization of some kinds of clover; for instance, 20 heads of Dutch clover (Trifolium repens) yielded 2,290 seeds, but 20 other h.eads... | |
 | Charles Darwin - 1955 - عدد الصفحات: 616
[ عذرًا، محتوى هذه الصفحة مقيَّد ] | |
 | Anon - 2006 - عدد الصفحات: 344
[ عذرًا، محتوى هذه الصفحة مقيَّد ] | |
 | 1907 - عدد الصفحات: 536
...indispensable to the fertilization of the heart's ease (Viola tri-color), for birds do not visit this flower. I have also found that the visits of bees are necessary for the fertilization of some kinds of clover; for instance, twenty heads of Dutch clover (Trifolium repens) yielded 2,290 seeds, but other heads... | |
 | New Zealand Institute - 1870 - عدد الصفحات: 508
...tricolor), for other bees do not visit this flower. From experiments which I have lately tried, I have found that the visits of bees are necessary for the fertilization of some kinds of clover ; but humble-bees alone visit the red clover (Trifolium pratense), as other bees cannot reach the nectar.... | |
 | William Lonsdale Watkinson, William Theophilus Davison - 1860 - عدد الصفحات: 576
...heartsease ; for other bees do not visit this flower. From experiments which I have lately tried, I have found that the visits of bees are necessary for the fertilization of some kinds of clover; but humble-bees alone visit the red clover, as other bees cannot reach the nectar. Hence I have very... | |
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