File:The natural history of plants, their forms, growth, reproduction, and distribution; (1902) (14578970328).jpg

Identifier: naturalhistoryof02kern (find matches)
Title: The natural history of plants, their forms, growth, reproduction, and distribution;
Year: 1902 (1900s)
Authors: Kerner von Marilaun, Anton, 1831-1898 Oliver, Francis Wall, 1864- Macdonald, Mary Frances Ewart Busk, Marian Balfour, Lady
Subjects: Botany
Publisher: London, Blackie
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

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of the insect-visitors.On a future occasion it will be necessary to enter more fully into the manner inwhich the insects that creep into the pouch take up and afterwards deposit thepollen, and it will therefore be sufficient to mention here that they are kept pri-soners there until the anthers have opened. When dehiscence has taken place, andnot before, the tubular middle region undergoes certain changes which make itpossible for the captives to escape from their temporary dungeon. 166 DISPERSION OF POLLEN BY ANIMALS. For flowers to serve as refuges and nocturnal haunts for insects they neednot necessarily be fashioned into hollow receptacles, pouches, bells, or anythingof the kind, as is proved by the following observation. In my garden the flowersof plants of Phlox paniculata, indigenous to North America, and of the CanadianGolden-rod (Solidago Canadensis), which bloom simultaneously in the autumn,were visited by numberless flies—particularly by the large bee-like Eristalis arhus-
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Fig. iAi.—Anstolochia ringens (After Baillon.) torum—which feasted on as much of the pollen as was accessible to them. Byday they stayed as readily on the Phlox-flowers as on the Golden-rod; but asnight approached they one and all migrated to the Golden-rod. Not a single flyremained on the Phlox, whereas the great bunches of Golden-rod capitula werecovered with hundreds of flies. On the following night, which was still and cold,I examined the flowers by the light of a lantern and found that less dew wasdeposited on the flowers of the Golden-rod than on those of the Phlox, and thisled me to conjecture that the temperature of the former flowers had risen in thenight above that of the surrounding atmosphere. And this turned out to be thecase. A thermometer inserted in the middle of the inflorescence of the Golden-rod, ALLUREMENTS OF ANIMALS FOR THE DISPERSION OF POLLEN. 167 which was in full flower, recorded a temperature about 2° higher than the environ-ment, and probably there wou

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