276 RELATION BET^VEEN CLIMATE AND VEGETATION 



the elevation being from 3000 to 3500 feet above the level of 

 the sea. In the account which I shall presently give of my 

 visit to the summit of those mountains, which is more than double 

 that elevation, I shall have occasion to mention several species 

 which may be cultivated in a much cooler temperature. An- 

 other reason why no general rule can be laid down for the 

 cultivation of these plants is, the great variety of soil and situ- 

 ation which they affect in their native country ; some, like 

 Zygopetalitm Mackaii, are terrestrial, and grow in open ex- 

 posed places ; others, like Warrea tricolor, are also terrestrial, 

 but grow in the deep virgin forests ; some, like Zygopetalum 

 maxillare, are only found to inhabit a particular tree, while 

 others are found indiscriminately on all kinds of trees, on rocks, 

 and even on the ground ; some, like Lcelia ciimabarina, grow 

 in moist places on exposed rocks ; wliile others, like Cystopera 

 Woodfordii, grow in a similar soil, but in shaded places ; some, 

 like Maxillaria picta, grow on the most dry and exposed rocks, 

 while others, like Grobya Amherstice, grow also on dry rocks, 

 but generally in the shade. The soil is here very similar to that 

 around Rio, there being but little alluvium, except in the valleys, 

 anfl the under stratum consisting of the same red-coloured 

 argillaceo-ferruginous clay. Like the mountains around Rio, 

 the whole of the Organ range consists of granite. 



As I arrived on the mountains when the summer was setting in, 

 I was just in time to secure the first flowers of the season ; and as 

 my excursions extended in all directions to a distance of from 

 10 to 20 miles from Mr. March's house, I was enabled to obtain 

 a tolerably correct knowledge of the vegetable productions of 

 that part of the country. In the following short sketch I shall 

 merely mention what are the most common plants which are 

 peculiar to a few well-marked situations. In moist and marshy 

 places the shrubby vegetation consists of Melastomads, some of 

 which are beautiful large flowers, species of Pleroma., that rival 

 the Rhododendrons in the richness of their colours. Among these 

 are also to be seen a few species of Myrtle-blooms, and several 

 fruticose and suffruticose species of Verno?iia. The herbaceous 

 plants consist of Composites, the most common of which is a 

 large white-flowered Erigeron, several Jjtricularias, Drosera 

 villosa, different species of Ferns, one of which is the fine 

 Osmunda spectabilis, many species of Hegonia, Sedges, 

 Grasses, and terrestrial Orchids. In the pastures the turf 

 consists of different species of Grass, which belong princi- 

 pally to the genera Paspalum, Panicum, Chloris, &c. ; but it is 

 with no little difficulty that the pastures can be kept from 

 running into a mass of shrubs and underwood, from the rapidity 

 with which plants of those characters usurp the soil. Hence all 



