76 



DISTRIBUTION OF PLANTS. 



giving evidence, therefore, of standing trees on the river-bank at no 

 very great distance, nearer, in all probability, than the base of the 

 Andes. 



Negative chakacters. As in other Desert and excessively arid 

 countries, Cnjptogainous i^^^o^yds were exceedingly rare, almost wanting : 

 the aquatic A'iO^Za was indeed abundantly floating in the river; but 

 on the land, there were no signs of Ferns ; and only once was a Lichen 

 met with, growing in tufts on the stem and branches of a single 

 shrub. 



The following Tribes and Families of plants were not met with in 



our excursions : 







Ranunculaceae, 



Crassulaceae, 



Nyctaginacese, 



Eerberidaceaj, 



Ficoidacete,) 



Lauracefe, 



(Papaveracea3, 



Saxifragaceae, 



Thymeleaceae, 



Capparidaceae,) 



(Escalloniaceae, 



Elaeagnaceae, 



Violaceas, 



Cunoniacese, 



Aristolochiaceae,) 



Cistaceaj, 



Araliacese, 



Urticacefe, 



Hypericacese, 



Valerianacefe,) 



(Hypoxidaceae,) 



(Ampelidaceae, 



Carupanulaceae, 



Smilaceae, 



Linacese, 



f Lobeliaceae,) 



(Liliaceae, 



Geraniacese, 



Ericaceae, 



Melanthaceas, 



The Tribe Phaseolese, 



(Epacridacese,) 



Bromeliaceae, 



The Tribe Pomacese, 



Gentianaceae, 



Commelinaceae,) 



Melastomacefe, 



(The Tribe Convolvuleae, 



Araceas. 



Myrtaceae, 



The Tribe Antirrhinese, 





CucurbitaceBe, 



Orobanchaceae, 





The absence of Ericaceae and Epacridacese in an Austral region, 

 at first seems remarkable ; but may perhaps be accounted for under 

 the extreme aridity, by the entire absence of that spongy bog-like soil, 

 which is so prevalent over upland and lowland, wet or dry, in most 

 parts of the Southern Hemisphere. 



The specimens collected at the mouth of the Rio Negro, after being 

 prepared, were reviewed jointly by Mr. Brackenridge and myself; 

 when, with the living plants fresh in memory, as we examined the 

 specimens, I wrote down a List, including, as far as they could be 

 recalled, all the species we observed. The same plan was kept up 

 afterwards, throughout the remainder of the voyage. 



The transfer of the Lists to my Journal, usually after some days or 

 even weeks, was yet made before the living plants had faded from my 

 memory. The species were now entered in botanical order, according 



