378 FREAKS OF PLANT LIFE. 



brought to him in a condition in which it was un- 

 comfortably hot to the hand, but he had no ready 

 means of ascertaining the precise temperature. Mr. 

 Nicholson has observed PJiilodendron sagittcBfolmm 

 with the anthers nearly ready to dehisce, and which 

 exhibited a rise of temperature from 69°, that of the 

 stove, to 81° Fahr. Also of Philodendivn eximium, 

 when the house was at 82^^, showed an elevation of 

 92°. Seeing that the latter are aroids, in which 

 numerous flowers are associated, the rise of tempera- 

 ture was comparatively small. 



Somewhat more striking results were shown some 

 years ago by Mr, W. H. Tillet, of Norwich, on an 

 aroid growing in his conservatory, in which he 

 observed a manifest increase of temperature, and 

 found, by testing with a thermometer, that the eleva- 

 tion exceeded those above alluded to. It may be 

 accepted as a general result of numerous experi- 

 ments, that, in the large aroids, an increase of tem- 

 perature of fully 30° Fahr. may be anticipated, which, 

 under exceptionally favourable circumstances, may 

 reach as much as 50°. 



In palms and their allies the flowers are produced 

 in dense masses, and these are often wholly or par- 

 tially surrounded by an envelope, so that the physical 

 conditions are very similar to those of the aroids ; 

 yet opportunities do not often arise for determining 

 the heat evolved durinsf the flowering. Mr. Nicholson 



