160 SUMMARY OF CURRENT RESEARCHES RELATING TO 



heartwood, or when severely wounded. The writer does not agree with 

 Penhallow in regarding the Cordaitales as peculiar among the Gymno- 

 sperms in this respect, but claims that similar structures are found in 

 Finns, Picea, Larix, and Pseiidotsuga, and other Gymnosperms, also in 

 eleven o-enera of the Anarcadiaceae, and in two of the Araliace^. He 

 concludes that "resinous tracheids in Gymnosperms find numerous 

 parallels in the Angiosperms, that they represent one form of reservoir 

 for excretions, and that the form of the resin-masses is in response to 

 well-known physical laws." These structures somewhat resemble tyloses^ 

 and reduce the permeability of the wood. In a few cases— e.g. in Finns 

 albicatdis—ih.ej appear to have a certain value as a diagnostic feature. 



S. G. 



Flower and Fruit of Diaperia. — J. Briquet (Compt. Rend. Soc. 

 Fhys. et d'Hist. Nat. {Geneva), 1918, 35, 76-81) has studied the 

 morphology and biology of the flowers and fruit of D. prolifera, with 

 special reference'to the bracts surrounding the central flowers. The paleal 

 horns enclosing these flowers appear to throw light upon the probable 

 origin of the so-called pseudocarpic bracts. Before taking on the func- 

 tions of a pericarp, the bracts of this species serve as a protection for the- 

 flower, not by undergoing any great structural alterations, but by simply 

 folding themselves round the flower in the form of a horn. The 

 functions of a perianth are made still more evident by the woolly hairs- 

 of the central part of the capitulum being hooked together in such a 

 manner as to form with the bracts a simple structure in which the bees 

 must work somewhat laboriously to find the tiny corollas. Other new 

 facts noted in the present work are the orientation of the plan of 

 symmetry of the ovaries ; the presence of numerous mysogenous hairs 

 on the epicarp of the achenes ; the absence of fibro-vascular bundles in 

 the corolla of the female flower, and their presence in the corolla-tube, 

 but not in the lobes of the bisexual flowers. D. midticanlis differs from 

 D. inolifera in having sessile ovaries in the bisexual flowers, and in the 

 absence of the horn-like structure formed by the hairs and bracts ; these 

 differences being merely specific, the two species appear to form a natural 

 group. The author considers that there is not sufficient ground for 

 uniting this genus with Evax, as proposed by Gray, but suggests the 

 need for a detailed study of the morphology of the Filagineaj. S. G. 



Interrelationships of the Taxinese. — M. C. Bliss {BoL Gaz., 1918, 

 66, 51-60, 2 pis.) has studied the root and stem of Uephalotaxus, 

 Torreya and Taxiis, with special reference to the classification and 

 relationship of the Taxineae. Owing to want of material it was not 

 possible to study the process of recapitulation in the embryo and seed- 

 ling, but retention of ancestral characters was clearly visible in the root 

 and 'stem, especially in Taxus. The abundance of resin-parenchyma in 

 the root and stem of Cephalotaxus proves the close connexion of this 

 genus with the Podocarpineaa, while the smaller amount in the stem of 

 Torreya points to the intermediate position of this genus. The resin- 

 parenchyma in the root of Taxus cuspidata and T. baccata, and also in 

 the wounded stem of the latter, is evidently an ancestral feature, while 

 its entire absence in the normal stem of T. IrevifoUa points to the more 



