MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 1 27 



that the ordinary aerial stems usually form but few leaves before 

 reaching a length of a meter or two, hence this is a vine which does 

 not show excessive elongation, or suppression of organs to any marked 

 extent, in etiolation of awakening shoots. The epidermal cells were 

 smaller in all dimensions than the normal, and the stomata which 

 seemed to be present in normal numbers were functional. The hairs 

 were hardly so numerous as in the normal. A normal collenchy- 



FiG. 83. Menispermum Canadeiise. Partial transverse section of normal stem. 

 A, epidermis; B, subepidermal layer; C, cortex; Z>, bast fibers; E, xylem ; F, 

 xjlem parenchyma. Cambium and sieve tissue are to be seen between D and E. 



matous subepidermal layer was lacking in the etiolated stems, and the 

 cortex showed an increase both in number and size of the elements, 

 and contained no intercellular spaces in either instance. The etio- 

 lated cortex showed five to eight layers of cells and the normal but 

 three or four. 



The bast fibers formed a complete cylinder in the normal, while in 

 the etiolated stem they are represented by elongated elements with 

 walls but little thicker than the cortical cells, and the groups external 

 to the separate bundles did not fuse or extend into each other. The 

 sieve cells seemed to be quite as well differentiated in the etiolated 

 specimen as in the normal, although not so numerous, and the lumina 



