No. 1, July, 1920] lii vsiolo(jv 237 



to 12°C., hut very i 'ly al room temporal ure. The hydrogen-ion concentration wu found to 



increase as after-ripening progressed. For Sambucu the high germin 



was obtained by layering fresh seeds out-of-d s over winter. No satisfactory forcing igenl 



was found. Drying probably injures the seeds somewhat bul is nol the only cause for tl 

 poor germination. Wha1 other cause or < there may be the author has nol been abL 



determine. Dormancy in Rubv is thoughl to be due to the high breaking strength of the 

 endocarp. Ready germination was obtained with seeds thai had been treated with concen- 

 trated B«S( >, for two I tours, rinsed in an i < - of eold water, the remaining acid neutralii 

 with sodium bicarbonate and the seeds rinsed again with water. -D. II. Eo e. 



1575. Webb, R. W. Studies in the physiology of the fungi X. Germination of the spores 

 of certain fungi in relation to hydrogen ion concentration. Ann. Missouri Bot. Gard. 6:201 

 222. Fig. 1-5. 1910. — Spores of Aspergillus niger, Penicillium cyclopium, Fiuariwn 

 Botrytis cinerea, and Lenziii* sdcpiand were germinated in solutions of M/5 mannite which 

 were adjusted to various P H values by use of ortho-phosphoric acid and sodium hydroxide 

 solutions. For all of the fungi studied; with the possible exception of Fusarium, ihe opti- 

 mum active acidity for germination was on the acid side of neutrality, inhil.it ion being i 

 deuced at or above P H 2.8. Hydroxy] ions appear to be relatively more toxic than hydrogen 

 ions. — S. M. Zeller. 



REGENERATION 



1576. Coulter, J. M. Regeneration in Phegopteris. [Rev. of: Brown, Elizabeth \V. 

 Regeneration in Phegopteris polypodioides. Bull. Torr. Bot. Club 45:391-397. 3 fig. 191 '> 

 (See Bot. Absts. 2, Entry 737).] Bot. Gaz. 67: 183. 1919. 



1577. Massart, Jean. Sur la polarite des organes vegetaux. [On the polarity of plan, 

 organs.] Bull. Biol. France et Belgique 101:475-483. 8 fig. 1918.— The author gives re- 

 sults obtained from experiments made upon polarity dealing with 30 different species of 

 plants. He concludes that there is no uniformity in the polarity of stems; that branches are 

 more sharply localized than roots; that root polarity determines not only the point of origin of 

 new roots, but also provides for the absorption of liquids at the proximal end and the trans- 

 mission of these liquids toward the distal end; and that the loss of root polarity is correlated 

 with the habit of the plant. Further experiments were conducted to ascertain the effect of 

 various external stimuli upon polarity. These were so controlled that opposing factors, such 

 as light and darkness, dryness and humidity, etc., were forced to exert their influence in 

 different combinations. Three species were employed, and six different combinations were 

 arranged for each species. The results obtained are indicated diagrammatically. — P. D. 

 Strausbaugk. 



1578. Taylor, William Randolph. On the production of new cell formations In plants. 

 Contrib. Bot. Lab. Univ. Pennsylvania 4:271-299. PI. 71-78. 1919.— See Bot. Absts. 3, 

 Entry 2450. 



TEMPERATURE RELATIONS 



1579. Akerman', A. Vaxternas kold-dod och frost-hardighet. [Winter killing and frost- 

 resistance of plants.] Sver. Utsadesf. Tidskr. 29:61-85. 1919. — This is a discussion of the 

 more practical aspects of the problem of tissue injury and death due to low temperature. 

 Previous work is reviewed. Experiments are described bearing on the temperature curve of 

 freezing tissue, on the effect of rapid thawing, on the effect of previous exposure to high or 

 low temperatures, and on the relation of killing temperature to carbohydrate content. Con- 

 stant low temperatures are maintained with the aid of carbohydrates. Results of sugar de- 

 terminations of different varieties of winter wheat show that the more resistant varieties have 

 a higher sugar content. The practicability of the use of relative sugar content as an index 

 of probable winter resistance in breeding for winter resistance in cereals is also discussed.— 

 E. G. Anderson. 



