738 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Irritability. 



Morphological Variation in Leaves of the Vine as a consequence 

 of Grafting.* — A. Jurie has continued his study of the effect of graft- 

 ing on the vine, and finds that well-marked modifications in the angle 

 of the veins, in the general form of the leaf, and in the presence or 

 absence of a tomentum, follow the grafting of certain vines on different 

 American stocks. Thus, after ten years' growth on a glabrous-leaved 

 American stock, the leaves of a Hungarian vine, which are naturally 

 tomentose, are almost glabrous. 



The instances cited illustrate a great variability in certain morpho- 

 logical characters of the vine leaf under the influence of the grafting 

 operation. They show clearly that this influence is specific, and sug- 

 gest a sort of asexual hybridisation between the two plants thus asso- 

 ciated. They afford a further justification of M. Lucien Daniel's theory 

 on variation in grafts. 



General. 



American Species of Thinnfeldia.t— E. W. Berry gives a detailed 

 description of the American species which have been referred to this 

 genus. The genus was established by Ettingshausen to include certain 

 fern-like fossils from the European Jurassic, which from their resemblance 

 to the recent Phyllocladus he referred to the Coniferae. Much diversity 

 of opinion has existed as to their true affinity. The American forms 

 embrace two distinct types of plants. Those from the older Cretaceous 

 beds, and from the Triassic, apparently represent true ferns comparable 

 with the European type. But the middle and upper Cretaceous species 

 are much larger-leaved, plants, and some of them have a wide distribu- 

 tion, in contrast to the restricted distribution of members of the first 

 type. These, the author is convinced, should be included in the coni- 

 ferous family Taxaceaj. They may perhaps form a link between the 

 Podocarpeaj and the Taxeas, and while they are unmistakably related to 

 Phyllortadus, their large size and other differences suggest their reference 

 to a new genus — Protophyllocladus — under which the author places three 

 species previously described under Thinnfeldia. To the latter genus 

 are restricted those species, of which the author recognises six in 

 America, which are presumably of fern affinity. 



Revision of the Family Fouquieracese.J — G. V. Nash publishes a 

 systematic revision of this small family of Dicotyledons, and discusses 

 its affinities. As revised, it contains two genera : Fouquieria, with six 

 species, and Idria, which is monotypic, and is confined to Mexico, the 

 Southern United States, and Lower California. The order, which was 

 considered by Bentham and Hooker in the Genera Plantarun as a tribe 

 of Tamaricacese, was separated by Engler on account of its oily endo- 

 sperm and gamopetalous corolla. This separation is upheld on geo- 

 graphical grounds, the new order being confined to North America, 

 while Tamaricaceaj without it is strictly Old World. The author of 

 the present revision suggests that its relationship is rather with Pole- 

 moniacere among the Sympetalas. 



* Conrites Bciulua, cxxxvii. (1903) pp. 500-2. 

 + Bull. Torr. Bot. CI., xxx. (1903) pp. 4::8-15. % Tom. cit., pp 4i9-;>9. 



