. Nature sketches in temperate America, a series of sketches and a popular account of insects, birds, and plants, treated from some aspects of their evolution and ecological relations . e basswood blossoms had pollenin their baskets, Miiller concluded that these insects visitedthe flowers for the honey and not for the pollen. There is anexplanation of the cause of the diverse forms of insect frequentersto the basswood blossoms if we remember the observations ofKnuth: First, the more specialized a flower — , the morecomplex its structural arrangements and the more deeply seatedits nectar —
. Nature sketches in temperate America, a series of sketches and a popular account of insects, birds, and plants, treated from some aspects of their evolution and ecological relations . e basswood blossoms had pollenin their baskets, Miiller concluded that these insects visitedthe flowers for the honey and not for the pollen. There is anexplanation of the cause of the diverse forms of insect frequentersto the basswood blossoms if we remember the observations ofKnuth: First, the more specialized a flower — , the morecomplex its structural arrangements and the more deeply seatedits nectar — the less are its insect visitors indiscriminatelydrawn from the entire insect fauna of a district, and the moredo they belong to one or several similar species adapted topollination. Secondly, the flatter and more superficial theposition of the nectar, the more varied are the visitors in differentregions, and the more are they indiscriminately drawn fromthe entire insect fauna of the region in question. ^ The basswood blossoms, shown in the plate illustration, • Mtiller, Fertilization of Flowers, p. Handbook, Vol. I, 1906, p. 196. ADAPTATIONS IX ANIMALS AND PLANTS 35. Insect Visitors to the Basswood Blossoms {Tilia americana). The insect on the flower to the right is a honey bee: the one to the left and the one flying are Syrphus flies {tiphaerophoria cylindrica). The lower insect is a small beetle flying. 36 NATURE SKETCHES IN TEMPERATE AMERICA have the nectar sliallowly held in the hollow sepals accessibleto a great \ariety of insect guests. 1he scent of these flowersis perceived for a distance of se\eral hundred yards; the parafBn-oids composing it have the jjeculiar property of increasing inintensity the farther away the perfume floats on the air up toa certain distance, when it finally disperses by diffusion throughthe air. In view of these facts, it is not difficult to ])erceivewhy the iieclar gatherers have preference for the Itasswoodflowers.
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