PHYTOGEOGRAPHICAL REMARKS. • 485 



Monniera trifolia is very common as well as different species of Polygala. 

 Among the Euphorbiaceae the genera Caperonia and Euphorbia must be 

 especially mentioned ; among the Malvaceae Malachra and Pavonia; among 

 the Sterculiaceae Melochia and Waltheria ; among the Ochnaceae Sauvagesia; 

 among the Turneraceae Turnera and Piriqueta. A very important part is 

 occupied by the Melastomataceae. Of these especially the genera Pterolepis, 

 Tibouchina, Comolia, Acisanthera, Desmoscelis and some Miconias draw 

 our attention by their generally small but elegant flowers. Also Gentia- 

 naceae are represented in many specimens, especially the genera Cou- 

 toubea and Schultesia, and of the Loganiaceae a few species of Spigelia. 

 Some species of Solanum rise above the lower herbs, while in some 

 savannahs on the Upper Para river and near Bergendal Amasonia erecta 

 colours the whole plain red by its purple bracts. The Rubiaceae are re- 

 presented bij numerous specimens of Mitracarpus frigidus and by a 

 number of species of Borreria and Diodia. Compositae on the other hand 

 are very scarce. 



Occasionally small groups of big shrubs and low trees grow on the 

 savannah, especially Curatella americana is noticed evereywhere, but also 

 different Myrtaceae and species of Clusia form these thickets. In these 

 Tetracera, numerous Malpighiaceae and some species of Adenocalymna 

 swing themselves. In July, after the great wet season the number of bloo- 

 ming plants in such savannahs is very great and offer the botanist a much 

 richer harvest than the primitive wood. 



Towards the south this little accidented territory passes into a low 

 mountanous country of chiefly archaical origin in which granite occupies a 

 very important place. Together with this the appearance of the river soon 

 changes. The irregularly rising bed causes rapids and waterfalls, between 

 which numerous, mostly densely overgrown greater and smaller islands stick 

 out. At the same time representatives of the curious family of Podosto- 

 maceae are found on the boulders in the strong current. Predominant of 

 these is Mourera fluviatilis which at high water develops below the surface 

 and in July and August, when the water falls, raises its pink bunches of 

 flowers above the level of the water. In October and November, when the 

 rocks are entirely denuded, the vegetative parts are found dried out, the 

 fruits spring open and spread their extremely fine seeds between the fissu- 

 res of the rock where they germinate under water when the wet season 

 sets in again. Besides Mourera a number of much smaller and less conspi- 

 cuous forms occur. The larger the islands in the rivers, the bigger the 

 trees that grow on them. On the smallest islets which are regularly flooded 

 in the rainy time, one finds on small quantities of silted down sand as a 

 rule some spare specimens of Cyperaceae. If the current does not become 

 too strong, shrublike species of Solanum are often found and Psidium poly- 

 carpon. If the islands are somewhat larger and higher, species of Cecropia 

 are very common. Low trees, generally having a xerophilous habit under 



