766 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Black Knot, Biologic Forms of. By E. M. Gilbert {Phyto- 

 pathology, vol. iii. pp. 246-247, Aug. 1913). — Black Knot (Plowrightia 

 morbosa) attacks Prunus virginiana and P. americana very commonly, 

 and P. pennsylvanica and P. serolina rarely. Plums and cherries, 

 even in the vicinity of badly diseased shrubs, are however not attacked 

 in Wisconsin. Cross infections with active spores of the fungus from 

 these different trees were unable to cause the production of typical 

 Black Knot, and it is therefore considered that Plowrightia morbosa, 

 like many other fungi, has several biologic forms. — F. J. C. 



Blue Gum in California, Yield and Returns of. By T. D. 



Woodbury (U.S.A. Dep. Agr., Forest Service, Circ. 210, November 8, 

 1912). — On account of its value from a purely commercial point of 

 view the cultivation of Eucalyptus — particularly the blue gum tree 

 (E. Globulus) — is receiving at present an increased amount of attention. 

 When properly cared for in the matter of thinning, the yield from 

 Eucalyptus plantations is very high, being probably only exceeded 

 in that way by the Redwood and Pacific coast Douglas Fir. — A . D. W. 



Bolleo-Chondrorhyncha x Froebeliana Cogniaux. By E. Miethe 

 (Orchis, vol. vii. pt. vi. pp. 86-88; 2 figs.). — This natural hybrid 

 is not an improvement on its parents. The flowers are yellowish 

 white suffused with blue. — 5. E. W. 



Boring Insects. By A. J. Cook (U.S. A. St. Com. Hort. 

 Cat., Bull. March 1912, vol. i. No. 4 ; 28 figs.). — Although there are 

 five orders of insects furnishing borers, the most destructive belong to 

 the Lepidoptera. 



The Californian Peach Borer (Sanninoidea opalescens Hy. Edw.) 

 is a very serious pest of all stone fruits. It is thought to work less 

 damage to trees on Myrobalan stock, and is more serious if trees are 

 injured, sickly, or grown in sandy soil. Except for its colour, this 

 insect is very similar to the Eastern peach borer (S. exitiosa) ; both 

 are beautiful wasp-like moths. The eggs are deposited on the trunk 

 of the trees near the earth. The larvae hatch in about two weeks 

 and commence feeding at once and eat into the cambium layer. 

 Washes and sprays are not reliable, the only method of control seems 

 to be digging out the larvae. — V. G. J. 



Bougainvillaea lateritia. By Dr. Georges V. Perez (Rev. Hort. 

 pp. 376-377, Aug. 16, 1913 ; plate). — The photograph in natural 

 colours represents a truly gorgeous mass of bloom yielded by this 

 plant in the open in the Canaries. Dark brick-red in colour, it has 

 spread luxuriantly over an adjoining group of Yuccas &c, and is 

 stated to flower throughout the year. A cherry-red variety of it is 

 stated to be even more beautiful. — C. T. D. 



Breeding of Plants (U.S.A. Dep. Agr., Year Book 1911, p. 409).— 

 Suggestions for breeding new and hardier races of plants from the 

 introductions recently received from Northern China and elsewhere. 

 A few portraits of wild apples &c. in native habitats.— E. A. Bd. 



