CRITICAL TEMPERATURES FOR PHYTOLACCA 



125 



development of seed, though at length after attaining a length 

 of about 1.5 cm., they failed and remained stunted. In the 

 plants lacking the red pigment the flowers remained unopened. 

 In the former case the red pigment was responsible for ameliorat- 

 ing the temperature conditions. On a high fog day the tempera- 

 tures indicated by a black and a clear bulb thermometer were 

 61° and 64° respectively at the height of the flowers, and this 

 difference may be taken to be as wide at any rate as that which 

 would be shown by the rosettes of a green and a red foliaged 

 plant. There can scarcely be a doubt that a prevailing tem- 

 perature a few degrees, not more than five, higher than 64° would 



TABLE 2 





* Seeded in 1915, blasted in 1916. 

 t Later blasted. 



have insured the setting and development of seed in the red 

 foliaged plant. 



Of the green foliaged plants one had been accidentally pros- 

 trated, so that the main stalk up to the first branching lay 

 within 10 cm. of the ground. Thereupon the axillary buds 

 developed a few small leaves and inflorescences. Those lying 

 within 10 cm. of the bare soil surface produced a few seeded 

 fruits, scattered among a majority of blasted ones. It seemed in 

 this case that occasional days, probably grouped in periods of 

 two or three, afforded favorable temperatures within 10 cm. of 

 the soil surface, due of course to the influence of the heat radiated 



