ILLUSTRATIONS (23). EFFECT OF A PINE-FOREST. 329 



of our companions in travelling from a port in the South 

 Sea through Mexico to Europe. Born in Quito, under the 

 equator, he had never seen needle-leaved trees , and folia 

 acerosa. The trees appeared to him to be leafless, and 

 because we were journeying towards the cold north, he 

 thought he recognised already, in the extreme contraction of 

 the organs, the impoverishing influence of the Pole. The 

 traveller, whose impressions I am here describing, and whose 

 name neither Bonpland nor myself can mention without 

 regret, was an excellent young man, the son of the Marquis de 

 Selvalegre, Don Carlos Montufar, whose noble and ardent 

 love of freedom courageously led him, a few years later, 

 to a violent, though not dishonourable, death, in the war of 

 independence, waged by the Spanish colonies. 



(24) p. 227 " Pothos plants, Aroidea" 



Caladium and Pothos are forms appertaining exclusively to 

 the tropical world, whilst the different species of Arum belong 

 more to the temperate zone. Arum italicum, A. dracunculus, 

 and A. tenuifolium advance as far as Istria and Friuli. No 

 Pothos has hitherto been discovered in Africa. The East 

 Indies possess several species of this genus (P. scandens and 

 P. pinnata), which have a less beautiful physiognomy and are 

 of less luxuriant growth than the American Pothos plants. 

 We discovered a beautiful true arborescent Aroidea (Caladium 

 arboreum), having a stem from 16 to more than 21 feet in 

 height, near the convent of Caripe, east of Cumana. Beau- 

 vois found a singular Caladium (Culcasia scandens) in the 

 kingdom of Benin.* In the Pothos form the parenchyma 

 occasionally expands to so great a degree that the leaf- surface 

 becomes perforated with holes, as in Calla pertusa (Kunth), 

 and Dracontium pertusum (Jacquin), which we collected in 

 the forests of Cumana. It was the Aroideas which first drew 

 attention to the remarkable phenomenon of the fever-heat 

 evolved by certain plants during the period of their inflo- 

 rescence, and which even sensibly affects the thermometer, 

 and is connected with a great and temporary increase in 

 the absorption of oxygen from the atmosphere. Lamarck, 

 in 1789, observed this increase of temperature in the Arum 

 italicum. According to Hubert and Bory de St. Vincent, 



* Palisot de Beauvois, Flore d'Oware et de Benin, t. i. 1804, p. 4, 

 pi. III. 



