ZOOLOGY AND BOTANY, MICROSCOPY, ETG. 



287 



BOTANY. 



(Under the direction of A. B. Rendlb, Isl.X., D.Sc, P.R.S., F.L.S.) 



GENERAL, 



Including the Anatomy and Physiolog-y of Seed Plants. 



Structure and Development. 

 Vegetative. 



Xylem Tissue in Cycads.— H. B. Sifton {Bot. Gaz., 1920, 70, 

 425-34, 2 pis., 1 fig.). A study of the primaiy and secondary wood 

 of Cycads indicates that the reticulate, alternate and opposite pitting 

 all develop from the scalariform type. The grouped, uniserinte and 

 scattered pits found in higher types result from the elimination of pits. 

 The Cordaites have similar pits, but they are not of so fixed a character 

 as in the Cycads ; the latter, like the Araucariacea^, have the more 

 primitive form of pit at the ends of the tracheids, in contact with the 

 parenchyma. Some Cycads have tertiary spiral thickening in the xylem, 

 while both the primary and secondary wood have bars of Sanio similar 

 to those of the Araucariacefe, together with other bars of an elongated 

 type. S. Greves. 



Morpholog-y of Cicer.— T. Holm {Bot. Gaz., 1920, 70. 446-.52, 

 3 pis.). An account of the mor-pholog j of Cicer arietinum ; the follow- 



Camh, 



Fig. 1. — Cross-section of young root of Cicer arietinuni. x 112. 



Ep., epidermis; C, cortex; Ejid., eudodermis ; St., stereome ; 

 L., leptome ; Canih., cambium. 



ing points are characteristic of this species. In the seedling stage the 

 cotyledons remain underground, the epicotyl is erect, and the first leaves 



X 2 



