NOTES AND ABSTRACTS. 



239 



at that distance from the ground throws out numerous branches, some of 

 which become elongated into flower-spikes. These often attain a height 

 of 2 feet, and vigorous specimens about 3 feet high furnished with several 

 blossoming flower-spikes present a most attractive and uncommon 

 appearance. It is valuable for conservatory decoration, being of very 

 distinct habit, and associating well with such subjects as are in flower in 

 July and August. — E. T. C. 



Cannas from Seed. By Jules Rudolph (Rev. Hort. Feb. 16, 1903, 

 p. 93). — To obtain flowers six months from sowing, the seeds are sown 

 at the end of January, either in river sand, sandy peat, or coal cinders, 

 burying very shallowly about 1 centimetre apart. They are then covered 

 with chopped sphagnum, put into warmth upon the pipes, and watered 

 frequently. They generally show in three weeks, and are potted in thimble 

 pots (8 centimetres) in Geranium soil mixed with one-third peat, the 

 pots being placed near the glass in a hothouse. Repot middle of March, 

 watering well and giving air, and pot on as required, the flowers forming 

 at next shift.— C. T. D. 



Caoutchouc Region of the Amazon, Ule's Expedition to the 



(Not. Konig. Bot. Berlin, hi. p. 224 ; March 1903). — A further account 

 of Hcvea brasiliensis and other rubber plants, with notes on the botany 

 and geographical distribution of these and other species, on the seeds, and 

 on various economic products met with on the journey. A price list of 

 numerous articles of food at Jurua in 1900-1901, at the end of the paper, 

 is worth noting. — M. W. 



Carbonic Acid Assimilation in Submerged Plants, Some 

 Material Influences on the. By Octave Treboux (Flora, vol. xcii., 1903, 

 pp. 77-97). — The experiments were conducted chiefly on Elodca (Anacharis) 

 in a dark room, so that the illumination by an incandescent gas lamp was 

 constant ; and precautions were taken against heating. Various substances 

 were added to the water, and the rate of assimilation estimated by the 

 classic method of counting the gas-bubbles given off in five minutes. 

 Assimilation is reduced by the addition of neutral salts. Salts. of the 

 heavy metals, alkaloids, and anaesthetics, which in minute proportions 

 increase respiration, have no such effect on assimilation ; chloroform arrests 

 it transitorily. All acids, when sufficiently dilute not to be harmful, 

 accelerate assimilation. Formic aldehyde, when sufficiently dilute not to 

 be harmful, was indifferent to the rate of assimilation as shown by the 

 bubbles ; but neither in the light nor in the darkness was any additional 

 starch formed therefrom — a most important result on theoretical grounds. 



M. H. 



Cardamine, Monograph of the Genus. By O. E. Schulz (Engl. 

 Bot. Jahrb. xxxii. 1903, pp. 280-416 ; 24/4/1903). — A general account of 

 the morphology of the genus is followed by a discussion of its affinities, 

 geographical distribution, and the hypothetical origin of its subdivisions. 

 The larger part of the paper is occupied by a systematic account of the 

 genus and its species, with full descriptions, and notes on distribution. 



A. B. R. 



