AGRICULTURAL BOTANY. 827 



/, No. 10, pp. 1181-1229). — This report, in continuation of work on the influence 

 of gases on plants (E. S. R., 25, p. 434), gives the results obtained by the authors 

 in their study on the development and chemical products of potato, flax, and 

 various leguminous plants grown in dilute acetylene gas. 



Acetylene in various dilutions (from 0.69 to 0.038 per cent by volume) w.as 

 found to give marked contrasts in development as compared with those of the 

 control plants. For example, in dilute acetylene there was shown more glycerin 

 and fatty acid, but less sugar, fat, and amido compounds than in plants grown 

 in pure air. Corresponding to these chemical conditions and in part explained 

 by them are noted such physiological differences as heightening of turgor, 

 bursting of seedlings, checking of growth in length, augmentation of that in 

 thickness, etc. 



A bibliography is given. 



The influence of ultraviolet rays on higher plants, A. J. Kluyver {Sitzher.. 

 K. Akad. Wiss. [Vienna], Math. Natimv. Kl., 120 (1911), I, No. 10, pp. 1137- 

 1110, pi. 1). — ^After reviewing briefly similar studies by other investigators, the 

 author reports on his own experiments with ultraviolet rays from the mercury 

 vapor lamp on various plants in regard to the effect of these short wave lengths 

 on the life of the cells and on their coloring matters and starch. 



It is said to have been found that sevei*al higher plants are injuriously 

 affected by the mercury vapor light, this effect being attributed mainly to 

 radiations of shorter wave length than oiKj^u, and being prevented by interposi- 

 tion of glass plates of 0.2 mm. thickness, which are known to absorb nearly all 

 such short waves. It is held that such short solar rays are absorbed by the 

 atmosphere, rendering artificial protection to these plants unnecessary. The 

 injurious effects of waves longer than 300/a are said to be limited in case of 

 leaves to the epidermis, but sometimes to extend more deeply in case of stems 

 and roots. 



Anthocyanin appears, in general, to be not very sensitive to ultraviolet rays, 

 being removed only fi'om the lower leaf surface of Begonia discolor and that 

 simultaneously with the death of the epidermal cells. Chlorophyll is little, if 

 at all, affected by the longer waves, which alone are able to i^enetrate to the 

 parenchymatous cells. In isolated cases (Nerium oleander and older needles of 

 Taaiis haccata) the cuticle protected even the epidermal cells from the in- 

 jurious action of the shorter waves. Leaves of Mimosa pitdica showed stimula- 

 tion response to the ultraviolet rays. Destructive changes are said to have 

 been protluced in the woody walls of certains cells, and starch is said to show a 

 decrease on exposure to these shorter wave lengths. 



The influence of lig'ht on the flowering of Japanese hops and hemp, J. 

 TouRNOis iCompt. Rend. Acad. 8ci. [Paris], 155 (1912), No. k, PP- 291-300).— 

 The author reports further experiments (E. S. R., 26, p. 432) with Humulus 

 japonicus and Cannabis saliva in regard to their time and mode of flowering, in 

 the present cases as related to differences in illumination. 



Plantings of seeds were made on January 8 and 28, and the plants obtained 

 from each group showed, as in previous experiments, an early and a late flower- 

 ing period. The precocity of flowering in this case was augmented in cor- 

 respondence with early planting and the weaker illumination of the winter days. 

 Plants from seeds sown late in April and also those from sowings early in June 

 (normal) and grown in darkness from 8 a. m. to 2 p. m. daily, flowered much 

 more precociously than did plants normally illuminated but otherwise similarly 

 treated. 



The sexual anomalies previously noted are said to have been more accentu- 

 ated in plants obtained from the earlier winter seedings made in the i^resent 



