PHYTOGEOGRAPHICAL REMARKS. 487 



trees are often cut, as in the neighbourhood of bushnegro villages, where 

 the wood is often entirely impassable. Another result is that the woods, - 

 seen from the river, give the impression of being much denser than is 

 really the case. 



The extremely damp atmosphere which always prevails, fosters strongly 

 the growth of epiphytical ferns as species of Trichomanes and Polypodium. 

 Other epiphytes are much less numerous, however. Orchidaceae are only 

 in exceptional cases found so near the bottom that they can be captured 

 and also Araceae and Bromeliaceae inhabit only the highest branches of 

 the trees. On the other hand Codonanthe calcarata is pretty often noticed; 

 it serves as a dwelling place for ants here, in the same way as is described 

 for the Amazon district by Ule. Where the soil is very damp, saprophytes 

 are rather frequent. Especially Voyrias and the representatives of the rela- 

 ted genera Leiphaimos and Voyriella attain a great development, also the 

 Burmanniaceae and Helosis guyanensis. 



To form an idea of the systematic constitution of the wood is a matter 

 of extreme difficulty. As is well known of all rainwoods of tropical America, 

 the trees have only a very short blooming period, occurring with long 

 intervals. The result is that one very seldom meets a tree in bloom. Although 

 this circumstance is aggravated by the fact that from below the flowers 

 are often unnoticed, yet it is certain that their number is small, of which 

 fact one is easily convinced by looking at the tops of the trees from a 

 mountain. The few flowers seen on such an occasion must on closer 

 examination often be ascribed to epiphytes. Since moreover the trees only 

 bloom when they have reached a considerable size, it is clear that only 

 cutting can give information. Climbing is mostly impossible on account, of 

 the smoothness of the stem. 



Among the biggest specimens met, a number of species of Tecoma 

 must be mentioned first, of which Tecoma Leucoxylon occupies the first 

 place. Ceiba pentandra here also draws our attention by its size, while 

 Mimusops Balata is very general in some places. Species of Lecythis and 

 Eschweilera play an important part ; Couratari guyanensis is also often 

 remarked. The leaves are on the whole rather small and leathery, the stems 

 smooth and often white, of which Martiusia parvifolia is a good instance. 

 Stems wit strutting roots are also often met with. Tree-ferns, Alsophilaand 

 Hemitelia, are found, but they are not common, On the light spots of the 

 primitive wood Heliconia and Costus are often frequent, the former of which 

 is also very common in the primitive wood on the lower rivers. Different 

 species of Psychotria and Uragoga are conspicuous by their coloured inflo- 

 rescence and bracts. Bertiera guyanensis already becomes somewhat larger 

 and Xiphidium coeruleum is especially common in the dampest places. 

 Specimens of Miconia and Clidemia are commonly met with. 



This primitive wood, as far as is known, covers the whole country 

 without interruption as far as the southern border ; even the higher tops 



