No. 423.] WORTHERN POLYPETALOUS FLOWERS. 227 
whole valley, even that above the water, so filled with the scent 
of vine flowers that it seemed almost impossible they should be 
so far off. And yet the nearest vines on the banks were one 
hundred yards above the water and at least three hundred yards 
from the boat. Afterwards I found, when wandering through 
the vineyards, that the smell of the flowers close at hand was 
much weaker than at a distance, and was forced to the paradox- 
ical opinion that with increasing distance and diffusion over a 
wider area the scent does not diminish but waxes stronger.” 
Under cultivation the species are usually perfect, but when 
growing wild are mostly unisexual. Cross-fertilization, accord- 
ing to Knuth, is occasionally effected by the wind. As visitors 
to the flowers of Vitis vinifera there have been observed the 
honeybee, and various species of Halictus ; while of Coleoptera, 
notwithstanding the green flowers, there have been enumerated 
twenty-one species. Müller's statement that “beetles are only 
or mainly attracted to flowers by bright colors” does not agree 
with the many species observed on the flowers of the vine. 
Union of the carpels prevails in the order Malvales, which 
includes the two families Tiliacez and Malvacee. A part of 
the genera with the carpels distinct, or but slightly united, still 
preserves a more primitive stage in the evolution of the flower. 
As in the vine family, the flowers of the linden, or lime tree, 
depend on their strong scent, rather than upon their coloration, 
to attract pollinators. The greenish-white flowers of Tilia 
americana are in small drooping, cymose clusters, sheltered 
beneath a floral bract. The thickened concave sepals secrete 
and contain the honey, which a pubescent fringe prevents from 
escaping. A high value is placed upon honey made from the 
linden ; in some localities the leaves are also covered with a copi- 
ous secretion of a sweet liquid, and sugar has been made from 
the sap. The strong scent, which is more noticeable at a short 
distance than close to the tree, is very attractive to the honey- 
bee, many of which I have seen at work on the flowers in Maine. 
On T. ulmifolia in Germany Müller and Knuth collected eleven 
flies and seven bees. The absence of beetles I attribute not 
to the dull color of the petals, but to the inaccessibility of the 
drooping inflorescence, covered both by the leaves and the floral 
