] 82 PHYSIOGNOMY OF PLANTS. 



Palms, Yuccas, Aloes, tall-stemmed Ferns, some Aralias, 

 and the Theophrasta where I have seen it growing luxu- 

 riantly, different as they are in the structure of their 

 flowers, yet offer to the eye in the nakedness (absence of 

 branches) of their steins, and in the ornamental character of 

 their tops or crowns, a certain degree of physiognomic 

 resemblance. 



The Melanoselinuni decipiens (Hofm.), which is sometimes 

 upwards of 10 or 12 feet high, and which has been intro- 

 duced into our gardens from Madeira, belongs to a peculiar 

 group of arborescent umbelliferous plants to which Arali- 

 acese are otherwise allied,, and with which other plants which 

 will doubtless be discovered in course of time will be asso- 

 ciated. Ferula, Heracleum, and Thapsia, do indeed attain a 

 considerable height, but they are still herbaceous plants. 

 Melanoselinum is still almost entirely alone as an umbelliferous 

 tree ; Bupleurum (Tenonia) fruticosum (Linn.) of the shores 

 of the Mediterranean ; Bubon galbanum of the Cape, and 

 Crithmum maritimum of our sea-shores, are only shrubs. 

 On the other hand, the tropical zone, in which, according to 

 the old and very just remark of Adanson, Umbelliferse and 

 Cruciferse are almost entirely wanting in the plains, presented 

 to us on the high ridges of the American Andes the smallest 

 and most dwarf-like of all umbelliferous plants. Among 

 38 species of plants which we collected at elevations where 

 the mean temperature is below 10 Eeaumur (54.5 Fah.), 

 there vegetate almost like mosses, and as if they made part 

 of the rock and of the often frozen earth, at an elevation 

 of 12600 (13430 English) feet above the level of the 



