98 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



ber were placed in the control and dark chambers in the middle of 

 December. The first activity was observed in the specimens placed 

 in the dark chamber on January i8, 1902, at which time a number 

 of buds midway on the branches and on the middle portion of the 

 stem began to elongate. Later all buds on the main axis and 

 branches in the upper portion of the shoot perished and only those 

 froni the basal portion survived. These, however, showed a vigor- 

 ous growth. It was found that the upper part of the stems of all of 

 the plants had died as a result of the transplanting. It is noteworthy 

 that the awakening buds were all infra-axillary. On April 6 some 

 of the young etiolated branches had attained a length of 18-20 cm., 



at which time a photograph was taken 

 from which the accompanying drawing 

 was made. A few branches measured 

 twice this length on June 17, 1902. 



The etiolated branches assumed an atti- 

 tude very nearly vertical, in consequence 

 of which some of them were appressed to 

 the stem. No branching occurred except 

 in one or two instances. In such the up- 

 permost pair as well as the terminal bud 

 would elongate approximately equally. The 

 leaves on etiolated branches attained a 

 length of nearly a centimeter, but remained 

 small and bract-like, although giving some 

 imitation of the adult form. The hairs so 

 noticeable in the young normal stems and 

 leaves were present even on the older por- 

 tions of etiolated stems and were very 

 abundant on the younger portions. These 

 hairs consisted of a short upright stalk 

 bearing a slender ovoid capitate cell with its long axis parallel to the 

 surface. The branches retained their colorless aspect for some time, 

 and showed a slight tinge of brown in June, five months after their 

 appearance. 



The cross-section of the apical internode of the etiolated stem 

 showed the pith in the process of enlargement, a thin cylinder of 

 wood cells with an indistinct cambium layer. The bast fibers formed 

 an incomplete circle of spindle-form cells with but little thicken- 



FlG. 53. Cornus alterni- 

 folia. Normal branch. 



