VEGETATION AT SANTAREM 157 
the whole term of their existence in the water — 
had all of them some contrivance for sustaining 
their flowers high and dry until fertilisation had 
been effected, or indeed until the fruit was fully 
ripe. A Utricularia [U. quinqueradiata, sp. n.) 
deserves especial mention ; it is a small species, 
with submersed finely-divided leaves bearing 
numerous bladders ; but the flower-stalk, which is 
about two inches long, has midway a large in- 
volucre of five horizontal rays resembling the spokes 
of a wheel ; this floats on the surface and keeps the 
stalk always erect, and the solitary flower well out 
of water ; the whole recalling a floating night-lamp, 
especially as the large yellow flower may be con- 
sidered to represent the flame. 
The aquatics bred in the turbid waters of the 
Amazon have already been described in my account 
of the Ponta Negra (p. 113). 
On the margins of lakes, and elsewhere in moist 
sandy grounds, grew several small plants, distinct 
from those already mentioned of the shores of the 
Tapajoz ; such as several Milkworts (Polygalae) and 
Xyrides, the latter looking like miniature Daffodils. 
Polygala subtilis, H. B. K., and Burmannia capita fay 
Mart., two fairy little plants, both having nearly 
leafless stems and heads of cream-coloured flowers, 
but otherwise extremiely unlike in their structure, 
reappeared in a similar site on the Rio Negro, and 
again on the savannahs of the Orinoco. Pedis 
elongata, H. B. K., a Composite herb with a strong 
Tansy-like smell, abounds in the same places, and 
still more on the savannahs of Guayaquil. 
The vegetation of the upland campos has already 
been sketched as it appeared in November, after the 
