96 BOTANICAL GAZETTE [january 



"New species, varieties, and combinations from the herbarium and the collec- 

 tions of the Arnold Arboretum," by Alfred Rehder (pp. 44-60); "A phyto- 

 geographical sketch of the ligneous flora of Korea," by E. H. Wilson (pp. 32- 

 43); and the fifth paper by C. S. Sargent entitled "Notes on North American 

 trees" (pp. 61-65). — J* ^- C. 



Toxicity of alpha-crotonic acid. — Alpha-crotonic acid, in concentrations of 

 25-50 p. p.m., is very toxic to wheat plants. Its toxicity is markedly reduced 

 by the phosphate radical, as Skinner and Reid 12 show by using it in water 

 cultures of wheat with a three-salt medium varying according to the triangle 

 system. The crotonic acid does not affect the relative absorption of any one 

 salt, thus differing from some of the other toxic organic compounds studied in 

 Schreiner's laboratory. The real nature of the antagonism is not known. 

 J. J. Willaman. 



» 



New genera. — Nakai 13 has described a new genus of Oleaceae (Abelio- 

 phyllum), found in Corea. It is an endemic and related to Fontanesia 

 (Fraxineae), a monotypic oriental genus. 



Pennell 1 * 



limfolia c 

 13 species 



Kneiffi 

 J. M. 



Plant mucilage. 15 — The mucilage in cacti, mallows, tragacanth, and lilies 

 arises in special large cells by hydrolysis of the cellulose wall, a hydrocellulose 

 being an intermediate stage. These walls are not secondarily thickened. An 

 account is given of the reaction of these mucilages to various stains. — J. J. 

 Willaman. 



Germination. — Russell 16 finds that the germination of camphor seeds in 

 the commercial seed bed is greatly improved by removing the pulp. By pulping 

 the seeds the increase in the number of seeds of transplantable size amounted 

 to 60 per cent. — Wm. Crocker. 



"Skinner, J. J., and Reid, F. R., The influence of phosphates on the action of 

 alpha-crotonic acid on plants. Amer. Jour. Bot. 6:167-180. 1919. 



** Nakai, Takenoshin, Genus novum Oleacearum in Corea media inventum. 

 Bot. Mag. Tokyo 33:153, 154. 1919. 



x < Pennell, F. W., A brief conspectus of the species of Kneiffia, with the character- 

 ization of a new allied genus. Bull. Torr. Bot. Club 46:363-373. 1919. # 



* Lloyd, F. C, Origin and nature of the mucilage in the cacti and in certain other 

 plants. Amer. Jour. Bot. 6:156-166. 1919. 



16 Russell, G. A., Effect of removing the pulp from camphor seed on germination 

 and the subsequent growth of the seedling. Jour. Agric. Research 17:223-238. i9 I 9* 



