1897.] Proceedings of Scientific Societies. 363 
to Indiana. We should not for a moment suppose that the species are 
identical in structure, since the conditions under which they occur are 
so different. Attention was called to the great abundance of plants dis- 
seminated by the wind, as Cycloloma, Salsola, Solanum rostratum, 
Populus, Cercocarpus, “ Fire-weeds,” (Epilobium spicatum and Arnica 
cordifolia), Hordeum jubatum, Elymus sitanion, ete. Plant migration 
may be studied to better advantage in the irrigated districts of the 
west than elsewhere, partly because the water carries many seeds and 
fruits in a mechanical way, and partly because the soil is very favor- 
able for the development of plants. Instances were cited where several 
foreign weeds are becoming abundant, as Tragapogon porrifolius and 
Lactuca scariola. The latter, known as an introduced plant for more 
than a quarter of a century, is common at an altitude of 7,500 feet in 
Clear Creek Cafion. Once having become acclimated it is easy to see 
how Prickly Lettuce is widely disseminated. 
Collectors appreciate the great importance of giving more attention 
to conditions under which plants thrive, such as phases of development, 
soil, climate, and altitudinal distribution. Structures of plants are pro- 
duced to meet certain conditions. Under extreme conditions, protective 
devices are more pronounced. In discussing some of the plants, 
Warming’s classification into Hydrophytes, Xerophytes, Halophytes, 
and Mesophytes, was adopted. The Mesophytes of eastern Iowa were 
compared with some of the Xerophytes of western Iowa, such as Yucca 
angustifolia, Mentzelia ornata, Liatris punctata, ete. These increase 
in abundance in western Nebraska, and attain a maximum development 
in northern Colorado. In the foot-hills and mountains the Metophytes 
constitute a large class, although Xerophytes are common in dry, open, 
sunny places. The photosynthetic system is reduced to guard against 
excessive transpiration, which would otherwise take place at high alti- 
tudes. The thick rootstock of Alpine plants in dry, open places is an 
admirable protection against drouth and cold. In cafions where snow 
remains on the ground plants do not need this protection. Halophytes 
are not numerous in species and genera. Hydrophytes are abundant at 
higher altitudes, where they occur in marshes and along streams. 
February 15, 1897.—Professor J. H. Kinealy presented a prelimi- 
nary discussion of the Poley air-lift pump, a device for pumping water 
from artesian wells by injecting into the pump tube, at a considerable 
depth below the surface of the water, bubbles of air from an air com- 
pressor. 
Mr. Trealease exhibited two hair balls removed from the stomach of 
a bull in Mexico, and showed that they were composed of the pointed 
