MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 1 59 



much less than in the normal. The etiolated leaves were small and 

 bract-like and the terminal portion of the stem was recurved, bearing 

 the compact bud in a position favorable to piercing overlying layers 

 of soil or humus. (See Fig. 119.) 



The etiolated stems were not beyond 2 mm. in diameter in any 

 instance, which was less than the normal. The reddish tinge of the 

 etiolated stems was but little altered even in the oldest portions. The 

 walls of the epidermal and underlying layers were slightly yellow, 

 and indications of collapse were visible. No noticeable multiplica- 

 tion of the cortical elements could be detected. The formation of a 

 phellogen in the medio-cortex had begun. The bast fibers were 

 less thickened than in the normal, and were widely separated bv the 

 primary rays. The sieve cells were not distinguishable and cambium 

 could be made out only in places. The xylem components were 

 less highly developed than in the normal, and the walls of the 

 vessels were comparatively thin. (Figs. 122-126.) 



The basal portion of the oldest normal plantlets showed a dis- 

 tinct phellogen immediately underneath the epidermis and a loosely 

 arranged cortex, in which no phellogen could be found. The cortex 

 was richly loaded with chlorophyl. Numerous crystals in globular 

 clusters were to be found which seemed wholly lacking from the 

 etiolated. 



Quercus rubra L. 



Acorns of ^lercus rubra were placed in the soil in November, 

 1901, in the dark room, and control chamber and germinated within 

 a period of six months. 



Normal plantlets on June 23, 1902, were from 8 to 15 cm. in 

 height, with the internodes from 2 to 5 cm. long, inclusive of those 

 of the terminal portion of the stem. The crowding of the leaves, 

 owing to shortness of the uppermost internodes as in o^. -paltis- 

 tris, was therefore lacking, but in several instances contiguous inter- 

 nodes were shortened in such manner as make it appear that the 

 leaves were opposite or in whorls of three. 



The basal portions of normal stems were about 4 mm. in diameter, 

 tapering to half that amount at the tip. A few of the basal leaves 

 were bract-like, but most of them were of the normal adult type, 

 which, with the stems, were more or less pubescent. 



Etiolated plants of the same age as those described above had 

 attained a height of 30 to 35 cm., consisting of 10 to 12 internodes 



