FUNCTIONS OF FLOEAL ENVELOPES. 



231 



474. The following are some of Saussure's experiments: 



Name. 



Duration of 

 Experiment. 



Stock, single, 24 hours. 



Stock, double 



Tuberose, single 



Tuberose, double, 



Indian Cress, single,... 

 Indian Cress, double,.. 

 Brugmansia arborea,... 

 Passiflora serratifolia,. 



Gourd, male flower 10 



Gourd, female, 24 



Hibiscus speciosus, 12 



Hypericum calycinum, ...24 



Cob?ea scandens, 



Arum italicum, 



Typha latifolia, 



White lily, 



Castanea vulgaris, 



Oxygen Consumed 



By Flowers entire. 



11-5 times their voL 



7-7 



9- 



7-4 



8-5 



7-25 



18-5 

 7-6 

 3-5 

 5-4 

 7'5 

 6-5 



By Essential Organs 

 only. 



18' times their vol. 



9-8 



5- 



9-1 



16-3 



16- 



6'3 

 8-5 



7-5 

 30- 



475. While this oxidation is going on, carbon is given off in the 

 form of carbonic acid, and heat is developed by the combination between 

 the oxygen and carbon. Experiments have been performed by La- 

 marck, Schultz, Huber, Saussure, Brongniart, Vrolik, and De Vriese, 

 as to the amount of heat produced during flowering, especially by 

 species of Arum, Caladium, and Colocasia. These are plants in which 

 the floral envelopes are nearly absent, while the essential organs, the 

 torus and growing point, attain a high degree of development, forming 

 a spadix enclosed in a large spatha. No heat could be detected when 

 the contact of oxygen was prevented, either by putting the plants into 

 other gases, or by covering the surface of the spadix with oil. The 

 surface of the spadix is the part whence the heat was chiefly evolved. 

 The Arum cordifolium occasionally had a temperature 20 or 30 above 

 that of the surrounding air; Arum maculatum 17 to 20; and Arum 

 Dracunculus and other species still higher. The following observations 

 were made by Brongniart on the spadix of Colocasia odora. The spathe 

 opened on the 14th of March; the discharge of pollen commenced on 

 the 16th, and continued till the 18th. The maximum temperature 

 occurred at different hours. 



M . Temperature 



Maximum. above p the Air , 



14th March. 

 15th 

 16th 



3 P.M. 



4 



5 



4-5 Cent. 



10-0 



10-2 



Maximum. 



Temperature 

 above the Air. 



17th March, 5 P.M. 1 1-0 Cent. 

 18th 11 A.M. 8-2 

 19th 10 2-5 



476. Vrolik and De Vriese made a series of observations on the 



