NOTES AND ABSTRACTS. 



169 



perature of Java is about 10° C. higher than the average temperature 

 during the growing period in the temperate zones. 



(2) The results obtained are quite in accordance with Blackman's 

 views regarding physiological processes. — R. B. 



Rhododendron ambiguum {Bot. Ma-g. t. 8400).— Western 

 China. Family, Ericaceae; tribe, Ehodoreae. Shrub, closely 

 branched. Leaves, lanceolate, inches long, pale beneath. Scales 

 black. Corolla, 2 inches across, greenish-yellow. — G. H. 



Rhododendron japonicum {Bot. Mag. t. 8403).— Japan. 

 Family, Ericaceae; tribe, Ehodoreae. Shrub. Leaves, 3 inches long. 

 Flowers, 3|- inches across, rose-coloured. — G. H. 



Rhododendron spinuliferum (Bot. Mag. t. 8408). — China. 

 Family, Ericaceae; tribe, Ehodoreae. Shrub, tall and thin, 3-8 feet 

 high. Leaves, lanceolate, 1-lf inches long. Inflorescence, 4- 

 flowered. Corolla, red, tubular, glabrous; tube, 7 inches long; lobes, 

 5, imbricate,, regular. — G. II. 



Rhododendrons in China. By G. Forrest {Gard. Chron., p. 

 291, May 4, 1912; with illustration). — 140 species are stated to be 

 indigenous to China. Special mention is made O'f those on the Sung- 

 kwei-Longkong Eange. — E. A. B. 



Romneya trichocalyx. 0. P. Eaffill {Gard. Mag. No. 2993, 

 p. 186, March 11, 1911; plate). — A native of California nearly allied 

 to the well-known Romneya Coulteri. Flowers pure white, often four 

 to five inches in diameter, with a cluster of rich yellow stamens in the 

 centre. The calyx is oval and covered with a mass of hairs. It is 

 considered preferable to R. Coulteri, as it flowers more freely and has 

 very handsome silver-grey foliage.- — E. B. 



Roots, Oxidation and Reduction by. By 0. Schreiner and 

 M. X. Sullivan {Bot. Gaz. pp. 273-85, April 1911).— It is shown that 

 in productive soils oxidation by roots is strong, and in poor soils 

 relatively feeble. Whatever increases the development of the plant 

 increases oxidation by the roots. Oxidation is due to bodies capable of 

 fixing atmospheric oxygen in an active form. Eeduction stages are 

 prominent in the early stages of growth. — G. F. S. E. 



Roots, Reduction by. By 0. Schreiner and M. X. Sullivan (Bot. 

 Gaz. pp. 102-30, Feb. 1911). — The authors give a short history of the 

 literature dealing with the oxidizing power of the roots of many plants. 

 Wheat seedlings were found to have the power of reducing nitrates 

 to nitrites (in one case 6 parts per million). Eeduction was also 

 obtained with sodium tellurite and sodium selenite, but it is suggested 

 that this was due to the metabolic activity of the roots or to other 

 cbernical reactions, and not to a special reducing substance formed by 

 the roots.~G. F. S. E. 



