638 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Diaspis pentag-ona and its Natural Enemy. By Ant. Ber< 

 lese {Rev. Hort. d'Alg. p. 88; March 1912).— This insect reached 

 Europe from Japan, and, having increased enormously, became suffi- 

 ciently destructive to be under the ban of special laws. It was dis- 

 covered, however, that its appropriate parasitic enemy had not 

 accompanied it from its original home, but specimens of this Pios,pal- 

 tella Berlesei having been imported into Italy and increased by 

 cultivation, all trees infested with the Diaspis may now be treated 

 with Piospaltella. As a result of the new importation, the Diaspis has 

 ceased to give any anxiety to horticulturists in Italy. — M. L. H. 



Dioscorea, The Source of the Drug-. By Harley Harris Bart- 

 lett {U.S.A. Dep. Agr., Bur. PI. Intl., Bull. 189; 1911).— Dioscorea 

 qiiaternata (Walt.) Gmel. ; D. glauca Muhl, ; D. paniculata Michx. 

 (var. glahrifolia Bartlett) ; D. hirticaulis Bartlett ; D. floridana 

 Bartlett. 



According to Mr. C. G. Lloyd the rhizome of Dioscorea was first 

 brought to the attention of botanic physicians by Dr. J. L. Eiddell in 

 1835, though used before as a secret remedy. It is valuable in bilious 

 colic; known also as wild yam, and colic root. The " true " wild yam 

 (D. paniculata) becoming scarce, the "false" {D. glauca) had to be 

 taken instead, but is not so satisfactory. — C. H. L. 



Disinfection of Plants in Algeria {Rev. Hort. d'Alg. p. 117; 



April 1912). — A disinfecting station has been installed in Algiers for 

 all imported seeds and plants which arrive in the colony. All plants 

 are exposed in a specially constructed receptacle to the action of 

 hydrocyanic acid, produced by treating cyanide of potash with sulphuric 

 acid, and all cotton-seed coming from Egypt or America is soaked in 

 a weak solution of corrosive sublimate. — M. L. H. 



Dune Plants, Anatomy of. By Anna M. Starr {Bot. Gaz. 

 vol. liv. pp. 265-305; Oct. 1912; 35 figs.). — The author has examined 

 microscopically the stem and the leaf anatomy of a number of plants 

 growing both on the dunes and in mesophytic (moderately wet and 

 sheltered) situations. Careful measurements were taken of the thick- 

 ness of the whole leaf, epidermis, depth of palisade, thickness of lower 

 epidermis oi cuticle; and for the stem, of the number of vessels, average 

 diameter of vessels, thickness of walls of vessels and fibres and of 

 cork, &c. 



She finds that in the leaves of dune plants (xerophytic) there are 

 heavier collenchyma (17 cases) and sclerenchyma (19 cases), the outer 

 wall of the epidermis is heavier (18), the palisade more completely 

 organized (17), and hairs more abundant (12 cases). 



The leaves were all thicker in the dune forms, but with one 

 exception. Bud -scales are also thicker, and in most cases the outer 

 wall or cork. There is considerable seasonal variation in the 

 structure of the leaves. In 1911 (an abnormally hot season) the 



