358 PHYSIOGNOMY OP PLANTS. 



plants are assembled in masses and determine the aspect and charac- 

 ter of the country. The New Continent does, indeed, also possess 

 superb Alstromerise and species of Pancratium, Hscmanthus, and 

 Crinum (we augmented the first-named of these genera by nine, and 

 the second by three species) ; but these American Liliacese grow dis- 

 persed, and are less social than our European Iridese. 



(3) p. 244. "Willow Form." 



Of the leading representative of this form, the Willow itself, 150 

 different species are already known. They are spread over the North- 

 ern Hemisphere from the Equator to Lapland. They appear to in- 

 crease in number and diversity of form between the 46th and 70th 

 degrees of north latitude, and especially in the part of north of 

 Europe where the configuration of the land has been so strikingly 

 indented by early geological changes. Of Willows as tropical plants 

 I am acquainted with ten or twelve species, which, like the willows 

 of the Southern Hemisphere, are deserving of particular attention. 

 As Nature seems as it were to take pleasure in multiplying certain 

 forms of animals, for example, Anatidae (Lamellirostres) and Co- 

 lumbse, in all the zones of the earth; so are Willows, the different 

 species of Pines, and Oaks, no less widely disseminated: the latter 

 (oaks) Toeing always alike in their fruit, though much diversified in 

 the forms of their leaves. In Willows, the similarity of the foliage, 

 of the ramification, and of the whole physiognomic appearance, in 

 the most different climates, is unusually great almost greater than 

 even in Coniferae. In the southern part of the temperate zone of 

 the Northern Hemisphere, the number of species of willows decreases 

 considerably, yet (according to the Flora atlantica of Desfontaines) 

 Tunis has still a species of its own, resembling Salix caprea; and 

 Egypt reckons, according to Forskal, five species, from the catkins 

 of whose male flowers a medicine much employed in the East, Moie 

 chalaf (aqua salicis), is obtained by distillation. The Willow which 

 I saw in the Canaries is also, according to Leopold von Buch and 

 Christian Smith, a peculiar species, common however to that group 

 and to the Island of Madeira S. canariensis. Wallich's Catalogue 

 of the plants of Nepaul, and of the Himalaya, cites from the Indian 

 Bub-tropical zone thirteen species, partly described by Don, Roxburgh, 



