316 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 

 lucluding^ the Anatomy and Physiolog-y of Seed Plants. 



Cytolog-y, 

 including- Cell-Contents. 



Metachromatic Corpuscles of Germination.* — J. Beauverie has 

 investigated the pumpkin and Ricinus with reference to the evohition of 

 the globoids of aleurone grains, which he classifies as metachromatic 

 corpuscles. As the aleurone-grains disintegrate, the globoid gives rise 

 to red granules, which are scattered uniformly throughout the cell. 

 Later on, when the aleurone-grains have lost their individuality, these 

 granules fuse and finally disappear. The author regards them as similar 

 to the metachromatic corpuscles found in Cryptogams, since they have 

 similar physiological, physical, and chemical properties. There is no 

 evidence at present as to their function, although it is suggested that it 

 must be either that of reserve, or of a pro-enzyme. 



Cutinised Membranes of Aquatics.f — L, Geneau de Lamarliere has 

 investigated the nature of the epidermis of aquatic plants, and finds that 

 towards the exterior, the chemical nature is that of pectic compounds ; 

 in passing towards the interior, the pectic compounds gradually give 

 place to cellulose. In the purely pectic membranes, secondary sub- 

 stances are found — e.g. cutin, aldehydes, azotes, phosphates, silicates, 

 and more rarely lignin. In the cutinised regions there is a thin, peri- 

 pheral layer, the epicuticle, beneath which a thin cuticle develops. 

 Oenerally there is also an epicuticle in the vicinity of the internal air- 

 spaces, which is equivalent, both morphologically and chemically, to the 

 external epicuticle. Lastly, irregular cutinisation occurs in certain 

 plants, and the cutinized membranes have the same constitution as those 

 of the epidermis. 



Structure and Development. 



Vegretative. 



American Fossil Cycads.J — G. R. Wieland has published a mono- 

 graph on " American Fossil Cycads." After dealing with the internal 

 structure and giving new information concerning the anatomy of the 

 vegetative organs, the author describes the reproductive organs. He 

 shows conclusively that previous views as to the unisexual character 

 of the Bennettites flowers are incorrect. Numerous specimens have been 



* Comptes Rendus, cxliii. (1906) pp. 924-7. 

 t Rev. G6n. Bot., xviii. (1906) pp. 289-95. 



% American Fossil Cycads, 1906, viii. and 284 pp., with plates, Carnegie 

 Institute of Washington. See also Nature, Ixxv. (1907) pp. 329-30 (2 figs.). 



