ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 603 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Structure and Development. 

 Vegetative. 



Anatomy of Catalpa Hybrids.* — D. P. Penhallow gives the results 

 of his investigation of the anatomical details of the stem structure of a 

 hybrid Catalpa of doubtful parentage (the so-called Teas hybrid), and 

 three well-known species. He concludes that hybrid characters are ex- 

 pressed in the structure of the vascular cylinder as well as in external 

 alterations of form and colour. Also that the Teas hybrid is the pro- 

 duct of a cross between G. Kmnpferi and G. bignonioides, and that 

 G. speciosa has played no part in its production. This confirms the 

 conclusion already reached by Professor Sargent on the basis of external 

 morphology. The dominant characters of the hybrid, as expressed in 

 the internal structure, are those of the Japanese parent as similarly 

 shown in the external characters. The resultant characters are most 

 strongly shown in transverse section, less so in the tangential, and least 

 of all in the radial. The author regards the hybrid as representing a 

 new species comparable to the large number of species of Crataegus now 

 recognised by Professor Sargent. 



Leaf-Nervation in some Species of Bupleurum.f — H. E. Petersen 

 describes five types of arrangement of the secondary and tertiary nerves 

 in a series of species of this genus, and establishes therein four groups 

 of species. There is considerable doubt, however, as to whether these 

 represent natural groups. 



Water-Conducting Systems of some Desert Plants.^ — W. A. 

 Cannon, working at the Desert Botanical Laboratory of the Carnegie 

 Institution, has made a comparative examination of the structure of a 

 number of the native desert trees and shrubs, using individuals growing 

 under normal desert conditions and those which have been more or less 

 irrigated, that is to say, grown in greater or less proximity to water. He 

 finds that branches of irrigated plants are poorer in conductive tissue 

 than branches of the same diameter of non-irrigated plants. The 

 author remarks that this is an unexpected condition and of especial 

 interest in view of the small development of the water-conducting 



* Ainer. Nat., xxxix. (1905) pp. 113-136 (8 figs, in text). • 

 t Bot. Tidsskr., xxvi. (1905) pp. 343-376 (34 tigs, in text). 

 X Bot. Gazette, xxxix. (1905) pp. 397-408 (9 figs, in text). 



