270 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



altered opacity of the tissues made this difficult to determine with 

 accuracy, and the general color scheme was materially changed. 



The alterations of flowers in response to darkness have been the 

 subject of many investigations, but the results recorded by the vari- 

 ous workers who have interested themselves in this subject are 

 somewhat difficult of comparison. The chief difficulty in the inter- 

 pretation of the facts at hand consists in the fact that in some instances 

 plants were allowed to grow until the inflorescences and the flowers 

 were more or less completely formed and then the entire plant was 

 placed in a dark chamber, which might be opened and examined in 

 the full blaze of daylight at frequent intervals. In other instances, 

 plants were taken at an advanced stage as above, and the inflores- 

 cence, or the branch bearing it were thrust into a dark chamber more 

 or less imperfectly sealed against light, thus making a '• partial etiola- 

 tion." In still other researches the plants were taken at an earlier 

 stage and the inflorescence allowed to carry on its full development 

 in darkness, but with the remainder of the plant exposed to light. 

 All of these methods entailed inexact observations in which no control 

 of the temperature and humidity of the air around the flowers was 

 kept. Attention is to be called to the fact that the stimulation by 

 which darkened buds may be awakened by illumination of others on 

 the same shoot doubtless has a similar effect on flowers and that all 

 ''partial etiolations " must be disregarded in the effort to discover 

 the effect of darkness upon flower-formation. Furthermore, only 

 evidence may be admitted which has been obtained from plants in 

 which the entire development of the flower proceeds during the vege- 

 tative season in which it opens or blooms. Under these conditions 

 the conclusion is inevitable that flowers are not produced in darkness, 

 except in Hypopitys, and it is probable that a similar phenomenon is 

 exhibited by Ephiphegus, a chlorophylless parasite.^*" This is corre- 

 spondent to the results of etiolation of Coprintis and other fungi in 

 which spores are not perfected in darkness. 



Senebier ^'^^ relates that Mees observed that beets flowered in cel- 

 lars, and he himself describes his own observations in which tulips 

 and crocuses were seen to produce flowers in "partial etiolations." 

 The inflorescences of Narcissus, did not emerge from the etiolated 

 sheathing bracts and peduncles were seen to undergo excessive 



'*^Leavitt, R. G. Subterranean plants of Epiphegus. Bot. Gazette, 33 : 376. 1902. 

 '*^Senebier, J. Observations sur les fleurs du quelques plantes elevees dans I'ob- 

 scuritie, Mem. Physio-chimiques, 2: 99. 1782. 



