THE VEGETATION OF THE VIRGIN FOIIEST 
only near the rapids of tlie Mudinra. Other vm-ietios of palm, like 
the muru-imiru, and the creeping ja(!itara (Desmoncus), which grows 
to the leng’tli of 100 feet, while it does not exceed a finger in width, 
are IVmnd CAniry where, and are not peculiar to any part of the river. 
Though real groves of palms are not fomid on the Madeira and the 
Amazon, at least not on the extenshe scale of the coco-palm woods 
on the coast near Pemamhueo, or of the palmito groves [Euterpe aleracoAt) 
in Minas Geraes, Sao Paulo and Parana, m'c often found groups of 
hundreds of jialms, Avhose noble shafts and light feathery leaves imparted 
an enhanced charm to the spectacle of white-foaming cataracts, darlc 
reefs, and islets glondng in the liglit of the setting sun. Of the 
perfection exhibited by Nature in tlie 
most triflijig details, the shapes of the 
cross-sections of the. ribs of different 
palm-loaves give an interesting ex- 
ample. These ribs take a more or ^ 
less curved shape according to their t' ' 
weight ; and, as the fibres themselves 
more easily resist, as it appears, 
bruising and pressing than tearing, the s 
much more developed than the under 
one ; the glassy silieious skin being, 
besides, much thicker below than above, ^ 
and more pronormeed at the sides, just \ 
as is the case with the top and bottom 
plates of tubular wronght-iron girders. 
So perfect is the adjustnreut that the 
I'ibs of the uauassii-palm (No. 1 ), whose 
stiff leaves, standing v(.wtically at the end like those of all the Attalea 
species, present a large smdace to the wind, show a broader cross-section ; 
A\diich imparts greater lateral stiffness. No. 2 does not require this, as tlie 
feathery leaves of the rniu'u-mnru are horizontally placed, and therefore 
suffer less from the Avind. The ribs of the fan-palm. No. 3, have a 
roundish shape, ;is from the peculiar form of their leaves they are more 
exposed to torsion. As all these ribs, besides, are filled with a soft 
marrow, and as the hardest fibres are placed on tlie surface, it is 
evident that, if the iwoblem had been to construct a rib of the greatest 
mVPEREJJT TIUXSVr.nSE CUTS QP 
P.VLM-inB.S. 
