798 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



insects than A' and very much fewer of the injurious, which could find 

 but small encouragement where the honey is hidden. Class B' is found 

 by our observations to fall very markedly into two divisions : one division 

 contains the plants whose flowers belong to the rose-purple- lilac-blue 

 series, the other contains those whose flowers belong to the yellow-white 

 series. The latter is visited by less desirable insects than the former, and 

 therefore, as shown in Tables XII. and XIII., approaches A'. Both halves 

 of class B', as well as class A', obtain more desirable visitors in North 

 Central Europe than they do at Clova. Whether, as in Tables XIV., XV., 

 and XVI., we contrast Miiller's or MacLeod's or Knuth's and Verhoeff's 

 observations with ours, we see in each case that long- and mid-tongued 

 Hymenoptera make far more species visits in Germany or Flanders than 

 they do in Scotland, and that in Scotland short-tongued flies make far 

 more species visits than they do in Flanders and Germany." A valuable 

 list of literature is given in this paper. Part III. of this subject may 

 here be alluded to. It is entitled " Observations on the most specialised 

 Flowers of the Clova Mountains " (Ann. Bot. vol. xvii. No. 67, p. 539). 

 "We now publish our observations on the fertilisation, about Clova in the 

 Eastern Grampians, of the flowers specially adapted for the visits of bees 

 and butterflies. The next part of our paper will complete the series, and 

 will terminate with a general review." Fifty-seven plants of various 

 orders are dealt with, and they belong to classes F and H, F including 

 those suited to diurnal and nocturnal Lepidoptera, H those of the Lychnis, 

 Crocus, Viola, Orchis, TropcBolum, Pinguicula, Labiate, Explosive Legu- 

 minous, Leguminous, Digitalis, Erica, Simple Pendulous, Pyrola, Ga- 

 lanthus, and Campanula types. " We found that in class B' the blue-lilac 

 flowers attracted the best of the insects, that the rose-purple came next, 

 that yellow followed, and that white or eyed flowers came last. Experience 

 with classes F and H is different, and our figures are as follows : with 

 white at the top, rose-purple second, yellow third, and lilac-blue last." 

 This is but a chance example of many interesting and important points, 

 for which reference to the papers themselves must be made. — B. I. L. 



Flower-Stalk, Joints Of the. By J. Velenovsky (Beih. Bot. Cent. 

 xvi. pp. 289-300 ; with 2 plates). — Suggests that in all cases in which the 

 pedicel is jointed the part above the joint is really the perigone of the 

 flower. He finds that bracts never occur above the joint. The Malvacece 

 have an epicalyx generally supposed to be formed of bracts, but he considers 

 this to consist of stipular outgrowths of the sepals. — G. F. S.-E. 



Fluorine : Its Estimation in Soils and Plants, and in Smoke 

 Damage. By W. Gr. z. Leiningen-Wusterburg (Nat Zcit. Land-Forst. 

 ii. pp. 273-287, 321-330, 357-366; 1 fig.; 1904).— When trees and 

 plants are injured by smoke, it is known that fluorine-containing gases, 

 along with sulphur dioxide, are the chief poisonous agents. The quantity 

 of fluorine absorbed by plants is extremely small. Existing methods for 

 estimating the quantity are not exact enough, and the author describes an 

 improved process, for details of which the original must be consulted. 

 By his method he confirms that leaves of plants damaged by smoke 

 contain more fluorine compounds than healthy ones. — W. G. S. 



