26 PHYSIOGNOMY OF PLANTS. 



parasitically the trunks of aged and decaying forest trees : 

 succulent herbaceous stalks support large leaves, sometimes 

 sagittate, sometimes either digitate or elongate, but always 

 with thick veins. The flowers of the Aroideee are cased in 

 hooded spathes or sheaths, and in some of them when they 

 expand a sensible increase of vital heat is perceived. Stem- 

 less, they put forth aerial roots. Pothos, Dracontium, Cala- 

 dium, and Arum, all belong to this form, which prevails 

 chiefly in the tropical world. On the Spanish and Italian 

 shores of the Mediterranean, Arums combine with the suc- 

 culent Tussilago, the Acanthus, and Thistles which are almost 

 arborescent, to indicate the increasing luxuriance of southern 

 vegetation. 



Next to the last-mentioned form of which the Pothos and 

 Arum are representatives, I place a form with which, in the 

 hottest parts of South America, it is frequently associated, 

 that of the tropical twining rope-plants, or Lianes, ( 25 ) 

 which display in those regions, in Paullinias, Banisterias, 

 Bignonias, and Passifloras, the utmost vigour of vegetation. 

 It is represented to us in the temperate latitudes by our 

 twining hops, and by our grape vines. On the banks of 

 the Orinoco the leafless branches of the Bauhinias are often 

 between 40 and 50 feet long : sometimes they hang down 

 perpendicularly from the high top of the Swietenia, and 

 sometimes they are stretched obliquely like the cordage of a 

 ship : the tiger-cats climb up and descend by them with 

 wonderful agility. 



In strong contrast with the extreme flexibility and fresh light- 

 coloured verdure of the climbing plants, of which we have just 



