168 RELATION BETWEEN CLIMATE AND VEGETATION 



In the vicinity of tlie same town tliere are large marshy plains 

 wliich are constantly inundated in the rainy season and nearly dry 

 in the hot weather. These places are covered with a species of 

 Byrsonima with greyish leaves, which form large round heads 

 somewhat resembling in the arrangement of its branches tlie 

 Persian lilac of our gardens. 



The details of our expedition down the Araguay will shortly 

 be laid before the public. So far as botany is concerned there 

 is not much to say. The banks of the rivers offer nothing like 

 t!ie variety of vegetation that is found by pursuing the country 

 roads, and I did not collect more than one hundi-ed specimens 

 the whole time I was on this river- The first day I fell in with 

 notlung but a Croton and a Psidiitm, which had the banks 

 almost entirely to themselves ; a Cissampelos , whicli ran over the 

 white sand of the bank ; a Cassia, a Composite with a vanilla 

 scent, and two or three grasses. The animal kingdom was much 

 better represented. One family of plants has, however, had 

 many genera and species added to it, and is much better known 

 in consequence of this voyage, and that I afterwards made on 

 tlie Tocantiiis; I refer to the Podostemads. These little plants, 

 which at first sight look much more like Liverworts than 

 flowering plants, only flourish on tiie face of rocks which are 

 kept damp by the spray of some cataract ; wlierever a torrent 

 descends with violence, these Podostemads abound and flourish. 

 I had previously met with them in other parts of Brazil, but 

 nowhere in such profusion as here. One species, Moureru Wcd- 

 delliana, Tul., covered the rocks with its pretty spikes to 

 such a degree that the river seemed to flow over a bed of roses. 



The forest trees of the coiuitry traversed by the Araguay 

 resemble, as a general rule, those of other parts of Brazil ; 

 Mimoseae, Caesalpineae, great Myrtle-blooms, Sterculiads, Bigno- 

 niads. Fig trees, Cedrela brasilicnsis, Scldnus arroeira, Apeiha 

 Jangada, on Pao Jangada, from the bark of which excellent 

 cords are made ; the Landi, of which we built our canoes ; the 

 Pao d'Arco, &c. Amongst the Palms I saw thelndaia {Attalea 

 compta) and another species new to me, remarkable for the 

 4-rowed arrangement of its leaves, and called Anaja. At San 

 Joao das duas Barras, in the province of Para, the Rio Araguay 

 is joined by the Rio Tocantins, and flows with it to the 

 Atlantic, which is not more than 60 yards below the level of 

 the last mentioned town. The grand Bertholletia excclsa, 

 which furnishes Brazilian nuts, is one of the principal ornaments 

 of the forests of this district. 



What I have related concerning the navigation of the Araguay 

 is in many respects applicable to the Tocantins, wliich we began 

 to ascend on the 20th of July, after a few days' stay at San 



