508 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



he shows the means by which insect fertilization is accom- 

 plished in JJtricularia and Pyxidanthera. A third article, 

 on Hairs and Glandular Hairs of Plants, is accompanied by 

 a number of cuts illustrating the structure of the hairs of 

 plants belonging to several different orders. Professor Beal, 

 in conclusion, asks, " Why may not these glands also draw 

 nourishment from the particles of dust which fall on them 

 from the air, or from the particles of soil which, in many cases, 

 accumulate to such an extent as to completely cover some 

 portions of the plant? As root-hairs are active in absorbing 

 materials from the soil, including something from solid sub- 

 stances, why should not the active glands absorb materials 

 from the dust and fragments of soil ?" The cleistogamous 

 condition of the flowers of DantJionia spicata is noted by 

 Mr. C. G. Pringle in the Naturalist for April. He thinks 

 that the seeds borne at the top of the culm of this grass fall 

 in midsummer and germinate on the spot ; whereas the seeds 

 concealed in the culm are only set free by the breaking of 

 the culm in a high wind, and are consequently likely to be 

 blown to a considerable distance, thus aiding in the diffusion 

 of the species. Mr. Martindale, in the June number of the 

 same journal, confirms what Mr. Pringle states with regard 

 to Danthonia spicata, but does not find a similar state of 

 things in D. sericea. The Naturalist also contains an es- 

 say on the Transpiration of Plants, by Dr. J. M. Anders, 

 to which the George B. Wood prize was awarded. We 

 must also mention an excellent paper, by Professor Todd, on 

 the Distribution of Timber in Southwestern Iowa, with In- 

 ferences concerning the Origin of Prairies, also in the Natu- 

 ralist. The conclusion is as follows : " While acknowledsin * 

 that prairie fires, the amount and distribution of rainfall, the 

 nature of the soil, the temperature and inclination of surface, 

 that all may have more or less importance in explaining the 

 origin of forests and prairies, we may nevertheless be con- 

 vinced that the fundamental condition of forest growth is a 

 constant medium humidity of air and soil. Let us, therefore, 

 while not neglecting our pluviometers, look more carefully 

 to our hygrometers in the study of this subject." The Tor- 

 rey Bulletin contains two articles by Mr. N. L. Britton, 

 one entitled, When the Leaves Fall ; the other, When the 

 Leaves Appear. Two tables of dates accompany the arti- 



