844 TIE1V8, &C. PHYSIOQKOMY OF PLANTS. 



Pulla,) which is adorned with so many beautiful flowering 

 Alpine plants. M. myrsinoides ascends in the Paramo de 

 Guamani as high as 11,200 feet. By far the greater number 

 of the 40 species of the genus Myrtus which we collected 

 in the equinoctial zone, and of which 3 7 were undescribed, 

 belong to the plains and the less elevated mountain spurs. 

 We brought only a single species (M. xalapensis) from the 

 mild tropical climate of the mountains of Mexico ; but the 

 Tierra templada, in the direction of the Volcano of Orizaba, no 

 doubt possesses many yet undescribed varieties. We found 

 M. maritima near Acapulco, on the very shore of the Pacific. 



The Escallonice, among which E. myrtilloides, E. tubar, E. 

 floribunda are the ornaments of the Paramos, and remind us 

 strongly (by their physiognomical aspect) of the myrtle- form, 

 formerly constituted, together with the European and South 

 American Alpine roses (Rhododendrum and Befaria), with 

 Clethra, Andromeda, and Gaylussacia buxifolia, the family of 

 the Ericece. Robert Brown* has arranged them in a special 

 family, which Kunth has placed between the Philadelphia 

 and Hamamelideae. Escallonia floribunda affords by its 

 geographical distribution one of the most striking examples 

 of the relation existing between distance from the equator 

 and vertical elevation above the level of the sea. I would 

 here again borrow support from the testimony of the accurate 

 observer, my friend Auguste de St. Hilaire.f " MM. Hum- 

 "boldt and Bonpland in their expedition discovered Escallonia 

 floribunda in 4 south lat. at an elevation of 8952 feet. I 

 found the same plant in 21 south lat. in Brazil, which 

 although elevated is very much less so than the Andes of 

 Peru. This plant is of common occurrence between 24 50' 

 and 25 55 ; in the Campos Geraes, and I also met with it 

 again on the Rio de la Plata in about 35 lat., on a level with 

 the sea." 



The group of the Myrtacese, to which belong Melaleuca, 

 Metrosideros, and Eucalyptus, commonly classed under the 

 general denomination of Leptospermeae, produce partially, 

 wherever the true leaves are supplied by phyllodia (petiole- 

 leaves), or where the direction of the leaves is inclined to- 

 wards the unexpanded petiole, a distribution of streaks of light 



* See the additions to Franklin's Narrative of a Journey to tJu 

 shores of the Polar Sea, 1823, p. 765. 

 t Morphologic vegetale. 1840, p. 52. 



