30 EXPERIMENT STATION EECOED. 



between si)ecies of weeds aud the soils on which they grow is reported (E. S. R., 

 25, p. 28). i 



In each district investigated there appears to be a definite association, which 

 may be either local or general. If local the presence of a weed is considered 

 symptomatic of a certain soil, but not exclusively so. If the association is a 

 general one it is believed to indicate that this species is characteristic of the 

 same* type of soil in all districts. There was little evidence found to show an 

 association between weeds and certain crops. 



Toxic excreta of plants, F. Fletcher {Jour. Agr. 8ci., 4 {1912), No. 3, pp. 

 2-i5~2/,7, pi. 1).—In a previous publication (E. S. R., 20, p. 521), the author 

 showed an apparent antagonism of sesame to soi-ghum, the sesame plants not 

 maturing in the presence of the sorghum. The cause of this behavior was 

 attributed to toxic substances secreted by the sorghum roots. Field experi- 

 ments with maize and sesame have since been carried on in Egypt, and they 

 appear to show the excretion of toxic material by the roots of maize plants. 



The injurious influence of tarred roads on neighboring vegetation, L. 

 Mangin {Jour. Agr. Prat., n. ser., 22 {1911), No. 35, pp. 27i-277/, figs. 3).— On 

 account of conflicting opinions regarding the effect of tarring roads on neighbor- 

 ing vegetation, a commission has been appointed to consider the injury, if any, 

 to the trees and shrubs in the parks of Paris. A summary of the findings of 

 the commission is given, of which the essential conclusions have been noted 

 elsewhere (E. S. R., 25, p. 128). 



Herbage studies, I. — Lotus corniculatus, a cyanophoric plant, H. E. and 

 E. F. Armstrong and E. Horton {Proc. Roy. Sac. [London], Ser. B, S4 (1912), 

 No. B 57-'/, pp. //7i-//S.'/). — Tests have been made of bird's-foot clover (L. corni- 

 culatns) by means of sodium picrate papers for the presence of hydrogen cyauid. 

 In 1010 the authors concluded that this plant occasionally contained a cyano- 

 phoric glucosid and its corresponding enzym. The experiments were repeated 

 in 1911 with specimens of this plant from many regions, and the glucosid and 

 enzj'm were rarely absent. The experience has led the authors to correlate the 

 appearance in L. corniculatus of the cyanophoric glucosid and tbe attendant 

 enzym with conditions favoring maturity rather than luxuriance of growth. 



L. corniculatus major, or L. uliginostis, as it is sometimes called, has always 

 proved free from hydrogen cyanid, as have the species L. tctragonolobus, L. sili- 

 guosus, L. hcrtholetti, and L. jacohwun. 



The authors request botanists to test L. corniculatus by the above method 

 and report their results to them. 



Investigations on heredity, W. Johannsen {Fortschr. Naturiv. Forsch., 

 3 {1011), j)p. 71-136, figs. 27). — This is a discussion of heredity as it applies to 

 descent and segregation among plants and animals. A considerable bibliography 

 of the subject is given. 



On the cause of dimoi-phism in CEnothera nanella, II. H. Zeijlstra (K. 

 Akad. Wctcnsch. Amsterdam, Proc. Sect. Sci., 13 {1911), pt. 2, pp. 6S0-685, 

 pi. 1). — The author for a number of years has been investigating the dimorphism 

 of CE. nancUa, one of the forms which is said to have arisen by mutation from 

 an. lamarcJciana. A large number of plants of this species have been studied, 

 and the author has come to the conclusion that CE. nanella is quite constant in 

 its appearance when grown from seed. 



In 1!)05 among thes;e specimens dwarf plants were frequently observed, and 

 a study of them showed in the stems blackened masses, which were found to 

 be made up of Micrococcus. This bacterium is believed to be the agent causing 

 the malformation. 



Contribution to the study of buds, Perriraz {Bui. Soc. Vaud. Sci. Nat., 

 5. ser., .',(] {1910), No. 170, pp. J,Ji5-.'i58, figs. 7).— Anatomical and biological 



