NOTES AND ABSTRACTS. 



275 



2 plates). — This insect is not often present in such numbers as to prove 

 of economic importance, being usually kept in check by the weather, 

 the damage to the food-plants by rust, overcrowding, predaceous insects, 

 and parasites. When the infestation, which is most obvious in autumn 

 on account of the large white woolly ovisacs formed by the female 

 scale, is considerable, the result of the attack is seen in the patches of 

 dead grasses scattered through the meadows. The grasses most affected 

 are Poa pratensis ("June grass ") and Agrostis alba (" red top "). The 

 best remedial measure appears to be to burn the field over in the spring 

 before the eggs hatch out, and so destroy the whole generation. — F. J. C. 



Seeds, Longevity of (Leading article in Garcl. Chron. No. 1039, 

 p. 349 ; Nov. 24, 1906). — M. Becquerel has recently been making experi- 

 ments which carry on the work done by A. de Candolle on this subject 

 many years ago. Nearly 550 species belonging to thirty of the most 

 important families of monocotyledons and dicotyledons, the seeds of 

 which had been gathered from twenty-five to 135 years previously. 

 " The only seeds which have been proved to preserve their germinating 

 power for more than eighty years are those of Acacia hicapularis, 

 CytisiLS hiflorus, and Leucana leucocephala, which are protected by a 

 thick skin and possess reserves little subject to oxidation."— -G. .S'. iS. 



Selection, Importance of, in Vegetative Reproduction. By 



W. R. Buttenshaw {Bull. Bot. Dep. Trin. No. 48, p. 248 ; October 1905).— 

 Instances of improvement in flowering in violets, freedom from 

 disease in pineapple, reduction of thorns in oranges, and increase of 

 sucrose in sugar-cane from careful selection in choice of plants for 

 propagation. — E. A. B. 



Senecio Veitchianus. By " Anon." {Gard. Chron. No. 992, p. 455, 

 Supp. fig. ; December 30, 1905). — This bold and handsome groundsel 

 was found by Mr. E. H. Wilson in the highlands of Central and Western 

 China, at an elevation of from 4.000 feet to 8,000 feet, in moist and marshy 

 places. The flower stems are from 3 feet to 6 feet high ; the blossoms, 

 which are of a bright yellow colour, are 2^ inches in diameter and borne 

 on a nearly cylindrical raceme, often more than 2^ feet long. It seeds 

 freely, and will quickly establish itself if plenty of room and moisture be 

 given it. — G. S. S. 



Sodium Salts, Plant Peculiarities as shown by the 

 Influence of. By H. J. Wheeler {U.S.A. Exp. Shi. Rhode E, Bull 104, 

 February 1905). — A detailed account of experiments with various plants 

 to show the effects of sodium salts with and without potash, and in 

 some cases vdth lime. As a summary the writer says : — " The verdict 

 against the equality of soda (and potash) in plant-production, returned in 

 this experiment by the plants themselves, ought to remove any further 

 doubt. It cannot be disputed, however, that soda is of certain use in 

 some manner with many varieties of plants ichen the supply of potash is 

 quite limited, and also with at least a few varieties of plants even in the 

 presence of a fairly abundant supply of potash. It may be stated that 

 sodium salts seem to liberate at least phosphoric acid and potash, so 



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