658 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
tropous diptera for flowers with half-concealed honey ; hemitropous hy- 
menoptera for flowers with half-concealed honey, and especially for 
clustered flowers ; eutropous hymenoptera for bee-flowers, and less 
decidedly for clustered flowers ; lepidoptera for flowers with concealed 
honey, and for clustered flowers, less decidedly for bee-flowers. 
Anemophilous and Entomophilous Plants.* — Herr O. Kirchner 
claims to have observed that several plants usually described as ane- 
mophilous are occasionally entomophilous. The vine, though generally 
self-pollinated, is sometimes abundantly visited by insects, and may 
accidentally be wind-pollinated. The flowers of the mistletoe are visited 
by insects. The male flowers of the sweet-chestnut are abundantly 
visited by honey-bees, diptera, and coleoptera. Chenopodium Vulvar ia 
and album sometimes secrete nectar, and are visited by insects, as also 
are Blitum virgatum and capitatum. 
Perforation of Flowers by Insects, j — Prof. L. H. Pammel gives an 
account of the species of plants, wild or cultivated in America, the 
flowers of which are perforated, either by insects or humming-birds, for 
the purpose of obtaining the honey. The most frequent perforators of 
flowers are species of Bombus , both females and workers ; but the honey- 
bee also occasionally obtains honey in this way. In southern latitudes, 
the carpenter-bees belonging to the genus Xylocopa also do considerable 
injury to flowers, as also do wasps ; but these latter more often visit 
flowers already perforated by species of Bombus. The humming-bird 
Trochilus colubris obtains honey in this way from several flowers. 
Occasionally the perforation assists rather than hinders pollination. 
The author also describes the contrivances for cross-pollination in 
Phlomis tuberosa and P. Busselliana. 
(2) Nutrition and Growth (including: Germination, and Movements 
of Fluids). 
Energetics of Plant-life. J — By the term “energetics” Prof. W. Pfeffer 
expresses the transformation of energy or force on which depends the 
power of an organism to perform its functions. He discusses in detail 
the mode in which energy can be rendered useful to the plant in carrying 
on its various vital processes. The manifestations of this energy are 
taken up in succession, as displayed in the processes of growth and 
movement, in the movements of water, and in the local transport of 
nutritive substances. 
When the movements concern imponderable molecules, the pheno- 
menon takes the form of chemical energy. Chemical energy becomes 
directly transformed into mechanical when a chemical reaction causes a 
change in volume or the elimination of some substance, as, for example, 
when crystals of calcium oxalate are formed in the cell-wall, and, by 
their growth, force apart the particles of which the wall is composed. 
Chemical energy is the source of electricity in plants, and also of the 
* Jahrhft. Yer. Yaterl. Naturk. Wiirttemberg, 1893, pp. 96-111. See Bot. 
Centralbl., liv. (1893) p. 367. 
t Trans. St. Louis Acad. Sci., v. (1892) pp. 241-77 (2 pis.). 
X Abhandl. Math.-Phys. KlasseK. Sachs. Gesell. Wiss., xviii. (1892) pp. 151-276. 
See Biol. Centralbl., xiii. (1893) p. 98. 
