Record. lxvii 



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, Menizelia ornata, Liatris punctata, etc. These 

 increase in abundance in western Nebraska, and attain a max- 

 imum development in northern Colorado. In the foot hills 

 and mountains the Mesophytes constitute a large class, 

 although the 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 altitudes. The thick rootstock of alpine plants 

 in dry open places is an admirable protection against drouth 

 and cold. In canons where snow remains on the ground, 

 plants do not need this protection. Halophytes are not nu- 

 merous in species and genera. Hydrophytes are abundant 

 at higher altitudes, where they occur in marshes and along 

 streams. 



February 15, 1897. 



President Gray in the chair, ten persons present. 



Professor J. H. Kiuealy presented a preliminary discussion 

 of the Pohle air-lift pump, a device for pumping water from 

 artesian wells by injecting into the pump tube, at a consider- 

 able depth below the surface of the water, bubbles of air from 

 an air-compressor. Provisional means of determining the 

 efficiency of the pump were indicated. In the discussion of 

 the communication a comparison was made with the action 

 of an inverted Sprengel pump. 



Professor William Trelease exhibited two hair balls removed 

 from the stomach of a bull in Mexico, and showed that they 

 were composed of the pointed barbed hairs of some species 

 of prickly pear upon which the animal had unquestionably 

 fed. Attention was called to similar balls from the stomachs 

 of horses, but composed of the calyx hairs of crimson clover, 

 which had been described in 1896 by Mr. Coville, of the 

 United States Department of Agriculture. 



