294. MR. SPENCER LE M. MOORE—PHANEROGAMIC BOTANY 
I have already shown how greatly the flora of the primeval forest lying between 
Santa Cruz and Tapirapuan differs from that of the open country extending to the 
eastern bank of the Paraguay river. That such diversity should exist is not difficult to 
understand. The flora of the open country behind the forest (Campos de Tapirapuan), 
so far as my rapid visit enables me to judge, does not show much affinity to that of the 
district round Santa Cruz, although external features are the same in both districts. 
The interposition of a wide tract of forest land is undoubtedly answerable for this diversity. 
In the forest peculiar conditions of light, heat, and moisture prevail—conditions 
unfavourable to most plants adapted to the drier, hotter, and sunnier open country. We 
may, therefore, regard the forest as a dense barrier impenetrable from either side. 
Winged, bladdery, and pappose seeds and fruits might occasionally be conveyed by 
winds across this barrier, but this would not be likely to happen often if the strip of 
forest were broad. Berries and drupes, too, would not be distributed by birds, seeing 
how different is the bird-fauna of the forest on the one hand and of open land on the 
other, and for analogous reasons hooked fruits would be little likely to penetrate far. 
On the whole, then, so slight are the means of communication between two open regions 
separated by a broad strip of dense forest, that it would probably not be incorrect to infer 
more floristic dissimilarity under these circumstances than if we had to do with an 
equal breadth of water. Similarly, shade-loving forest plants would only occasionally be 
transported across extensive intervening dry districts freely exposed to the ardours of a 
tropical sun; and this obvious consideration leads one to believe that almost continuous 
forest must extend from the Upper Amazonian basin to that of the Upper Paraguay, 
most probably viá the Guaporé river. 
Lastly, a quickly flowing river like the Paraguay at and near Santa Cruz must, in some 
degree, tend to keep neighbouring floras distinet. Plants with edible fruits would indeed 
be disseminated by birds; but ordinary fruits and seeds, and often also those provided 
with wings or a pappus, &c., would fall into the water to be hurried away down stream. 
At Santa Cruz I was prevented by indisposition from paying much attention to the eastern 
bank of the river, but what little I saw of its flora pointed to decided floristic difference 
between the two river-banks, difference which, at the time, seemed to me accountable 
only in the way just mentioned. Further observations, however, may prove this impression 
to be unsupported by facts. 
The collection has been worked up partly at the British Museum, partly at Kew. At 
the former institution the Brazilian flora is illustrated by sets of Gardner, Spruce, Pohl, 
Blanchet, Sello, Peeppig, Von Martius, Bowie and Cunningham, Weir, Claussen, Widgren, 
de Mello, and Messrs. Ridley, Lea, and Ramage. Kew, with most of the above sets, boasts 
the splendid results of the intrepid Burchell’s wanderings in the eastern part of the 
country.* A fine set of Riedel's plants, a collection but poorly represented at the 
Museum, is also preserved at Kew; so, too, are Professor Trail's Amazon specimens, 
and a set of the very large and remarkable collections made by that enterprising veteran, 
* One cannot but regret that much of the * Flora Brasiliensis" should have been written without examination of 
British herbaria, especially the two under notice, For this reason, many nondescripts, chiefly of Gardner's and 
Burchell’s collecting, exist in this country. 
