16 ART. 3. K. ONO. 



I first took Prunus Laurocerasus and put it into saturated 

 air at 22° C. The secretion was at this temperature very active. 

 Then I lowered the temperature to 8°-6° C, and after ten hours 

 I could see that the secretion had decreased. Repeating the 

 same process several times, I got always the same results. 



With Prunus yedoensis, Excoecaria japo7iica, Vicia sativa, 

 Polygonum cuspidatum, P. sachalinense and Ligustrum lucidum^ 

 the secretion stopped entirely at a temperature of 8°-6° C. 



With young or scarcely active nectaries, the effect of cold 

 was still evident. At a temperature above 33° C, the nectaries 

 of Prunus Laurocerasus, P. yedoensis and Viburnum japonicum 

 ceased to secrete, and at 40° C, the leaf itself lost its activity. 

 c. Influence of light. 



On putting Ligustrum lucidum, Viburnum japonicum, V. 

 opulus, Prunus yedoensis, and P. Laurocerasus in a dark moist 

 chamber, I found that their young nectaries produced no nectar 

 at all, bnt their fully developed nectaries secreted in the dark 

 equally well as in the sunlight. 



Prunus Laurocerasus secreted in a dark place for three, 

 weeks, the washing being repeated daily. The secretion was always 

 ample in quantity. Prunus yedoensis in the dark produced 

 nectar thrice. The influence of light on the secretions of the 

 nectaries is, in short, of an indirect nature, except in the case 

 of Vicia and some Euphorbia}'' 



A specimen of Vicia faba, 20 cm. high, cultivated in diflused 



light, produced two blossoms, but their nectaries did not secrete. 



Another specimen of Vicia faba, cultivated in the open air exj)Osed to 



direct sunlight, had secreted nectar before the flower buds appeared. 



In Vicia, the secretion takes place from the lower stipules 



3) Conf. Haupt. 1. c. p. 28. 



