290 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



The origin of canker is, according to the author, due to the presence of 

 bacteria. In all cases of canker veins of a yellowish, brown, or almost 

 black colour spread from a canker wound into the sound wood for a dis- 

 tance of 30 cm. In the surrounding bark similar but shorter veins are 

 also present. The plant-cells traversed by these veins contain numerous 

 bacteria, which, when isolated, prove by inoculation experiments to be the 

 true cause of the disease. 



The bacteria of Apple-tree canker have the form of short rods divided 

 into two geminate spheres, and stain readily with fuchsin, methylene 

 blue, and Gentian violet. Cultures of this organism grow well in agar- 

 agar and gelatine, which they liquefy. 



The bacterium of Pear canker is not distinguishable from that of 

 the Apple at first sight, but behaves somewhat differently in artificial 

 cultures. 



The roots of Apple and Pear trees often exhibit swellings of various 

 sizes, and, although these never show canker-like wounds, they are con- 

 sidered to be caused by the same kind of bacterium forming canker on the 

 branches. 



Gummosis in the Peach, Apricot, Plum, and Cherry is also stated to 

 be caused by bacteria which form veins similar in character to those 

 present in the canker disease. The organism causing this disease differs 

 from that of canker in forming colonies of a yellow-orange colour, and 

 secretes in agar-agar transparent beads. — G. M. 



Canker- worm. By C. M. Weed (U.S.A. Exp. Stn,, New Hamp- 

 shire, Bull. 85, October 1901 ; figs. 5). — The life-histories of two moths, 

 Anisopteryx pometaria and Palcacrita vemata, the larvae of which eat 

 the leaves of Apples, are noted, and remedial measures suggested. 

 Greasebanding and spraying with Paris green, Scheele's green, or 

 arsenate of lead seem most effective. — F. J. C. 



Cannas, The Crozy Strain of Floriferous. By S. Mottet (Bev. 

 Hort. pp. 18-20; January 1, 1902).— A description of origin and develop- 

 ment during twenty-five years. — C. T. D. 



Canna, New Class called Sprenger. By C. Sprenger (Bull. 

 B. Soc. Tosc. Ort. 3, p. 66; March 1902). — Flowers superior to any class 

 of Canna hitherto known and cultivated, easily beating Canna Crozy and 

 the Orchid-flowered kinds. The plant is very robust, not tall, with very 

 broad, rounded, reddish or green leaves, inclined, and not rigid ; flowering 

 stems much branched with enormous erect spikes, each with forty or more 

 immense flowers, which in size surpass those of the well-known variety 

 Alemannia with Orchid-like flowers. They open at dawn and last much 

 better than thoso of Crozy. They suffer neither from wind nor sun. 

 The first to appear among the batch of seedlings was King Humbert I. 

 This plant produced from May to July five stems, bearing 530 flowers ; 

 after flowering these stems were cut off and some superphosphate and 

 potash was given the plant, which until the end of November produced 

 as many more flowers, so that the whole number formed during the six 

 months reached 1,078. The plant is sterile. Hitherto no seeds have been 



