 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
 | Rudolph Wilson Chamberlain, Joseph Sheldon Gerry Bolton - 1923 - عدد الصفحات: 396
...to the fertilization of the heart's-ease (Viola tricolor), for other bees 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, 20 heads of Dutch clover (Trifolium repens) yielded 2,290 seeds, but 20 other heads protected... | |
 | Alfred Louis Kroeber, Thomas Talbot Waterman - 1924 - عدد الصفحات: 606
...indispensable to the fertilization of the heartsease (Violo tricolor), for other bees 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 twenty other... | |
 | Winterton Conway Curtis, Mary Jane Guthrie - 1927 - عدد الصفحات: 610
...and clover is one of his most famous cases. Stated in Darwin's own language, this runs as follows: 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 re-pens) yielded 2290 seeds, but 20 other heads protected... | |
 | 1925 - عدد الصفحات: 980
...invariable rule that when a flower is fertilized by the wind it never has a gayly-colored corolla. "I have found that the visits of bees are necessary for the fertilization of some kinds of clover. * * * Bumble bees alone visit the red clover, as other bees can not reach the nectar. — Darwin: Origin... | |
 | 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... | |
 | 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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