134 EXPEEIMENT STATION RECORD. 



aid of external objects, aud also iu their ability to set fruit wlieu tripped. The 

 number of pods set is uot proportional to the number of flowers, as a smaller 

 proportion of pods is produced on many-flowered racemes than on few-flowered 

 racemes. 



"Automatic tripping takes place most frequently in hot sunshine. Humidity is 

 doubtless also a factor. Automatic tripping can readily be observed by focusing 

 a burning glass on open flowers or by simply bringing shaded flowers into the 

 sunshine on a hot day. 



" Insects are the natural agents of cross-pollination in alfalfa, but even 

 where they are scarce, good crops of seed may be produced. Bumblebees and 

 leaf-cutting bees (Megachile) are the most efficient insects to trip alfalfa 

 flowers. Honeybees secure much honey from alfalfa flowers, but trip only a 

 very small percentage of the blossoms. Night-flying insects are of negligible 

 value. Butterflies have never been observed to trip a flower during the course 

 of these studies. Rain or wind causes but few alfalfa flowers to become 

 tripped. 



"Automatic tripping with consequent self-pollination probably results in the 

 setting of as many pods as does tripping by insect visitors, at least in the West. 

 This conclusion is also in accord with the observation that excellent seed crops 

 are produced in sections where bumblebees and other insects capable of tripping 

 alfalfa flowers are decidedly scarce." 



Barley culture in Wisconsin, R. A. Mooee and A. L. Stone {Wisconsin Sta. 

 Bui. 212 (1914), rev. ed., pp. 20, figs. 9).— This revision (E. S. R., 25, p. 531) 

 contains additional data, together with a score card and directions for scoring 

 barley. 



The average yield of pedigree barley for 6 years as produced by members of 

 the Wisconsin Experiment Association is given as 34 bu. per acre as against 

 29.3 bu. with other varieties. Pedigree barley at the station yielded an average 

 of 44.8 bu. per acre for the 5 years, 1908-1912, while common barley grown by 

 Wisconsin farmers averaged for the siime period 27.7 bu. 



Cactus opuntia as a forag-e crop for arid reg'ions (Bol. Min. Agr., Indus, c 

 Com. [Brazil], 2 (1913), No. 4, pp. 141-150).— This gives notes on the cultiva- 

 tion and uses of this crop. 



Chilian clover, J. W. Hadfield (Agr. Gaz. N. S. Wales, 24 (1913), No. 10, 

 pp. 857-859, pi. 1, figs. 3). — This notes the trial of Chilian clover, TrifoUum 

 pratense pereime, which thrived at the Hawkesbury Agricultural College, 

 whereas all the other varieties of clover practically failed. 



Studies in variation of red clover, Edna C. Pammel and Clarissa Clabk 

 (Proc. lotca Acad. Sci., 18 (1911), pp. 41-53, pis. //).— This paper presents data 

 obtained in a study of variation in the number of flowers in heads, variation 

 in length of flowers (stamen tubes), and size of pollen grains for ftrst, second, 

 and third crops grown on black loam, black loam underlaid with gravel, and 

 alluvial soils. 



It is noted that " the second crop clover has more flowers in the head than 

 the first crop clover, and that black loam underlaid with gravel is the best 

 soil for the production of red clover." The range extended from 53 to 142 

 flowers per head, with a mean of 90.44. The length was found to vary from 

 O.G to 1 cm. The width of pollen grains \av\:, from 20 to 40 ft, and the length 

 from 28 to 08 fi. 



Pollination of clover, L. H. Pammel and Chablotte M. King (Proc. Iowa 

 Acad. Sci., 18 (1911), pp. 85-45, figs. 3).— This paper describes the structure of 

 the flower of red clover and data upon the visit of insects to flowers as ob- 

 served for various periods on different areas. In 814 seconds 381 visits were 

 recorded^ That clover is not self-fertilized was indicated iu the thrashing of 



