42 SEMI-CENTENNIAL OF TORREY BOTANICAL CLUB 
fitting than a very fine ostrich plume. Their shape and their 
method of drooping is exactly the same, and when one finds a 
cluster of them, with the individual fronds arching over from the 
center, the effect is indescribably handsome. The pampas grasses 
also present a lovely appearance. The entire flower stalk may 
reach a height of twenty feet or more. Its lower two-thirds is 
very leafy. Then there is an elongated bare peduncle surmounted 
by a panicle several feet in length. The branches of this panicle 
are exceedingly long and slender, so that the slightest breeze is 
sufficient to blow them out in a horizontal position at one side, 
giving a remarkably close imitation of a flag. The color of this 
flag ranges from light pink toarather dark purple. All travelers 
are captivated by the beauty of this grass, which grows in patches, 
rarely of any great extent, throughout the entire river valley. 
The clumps of shrubbery that are scattered over the plain belong 
very largely to the Mimosa family, especially in the lower part of 
the valley. As we ascend, other classes mingle with them and 
they become very much more abundant and larger, at length 
giving way to a heavy forest growth which extends quite to the 
river’s edge. In this region, especially after we reach the hilly 
section, the river bank is gay with Heliconias of several species. 
The inflorescences are of a brilliant red, largely variegated with 
bright yellow, and to a lesser extent with blue. Those of one 
group are strictly erect, with slender stiletto-like branches, while 
those of another are pendulous, several feet in length, and of a 
regularly sinuous form. Throughout the greater length of the 
river, the trees near the water are largely Cecropias, of a number 
of species, and are of very striking appearance. Some have simple 
trunks, their huge digitate leaves on very long petioles, and radiat- 
ing directly from the summit to form an umbrella-shaped crown, 
while others have a few loose and open branches. The trunks 
and branches of all are very light colored, appearing whitish at a 
distance when the sun strikes them. Most of them have hollow 
stems and branches which are inhabited by colonies of fiercely 
stinging ants. Back of these 'ambaibas" comes a growth of 
Ceibas or silk-cotton trees, which are even more conspicuous, and 
are stately in their beauty. These trees have tall, straight trunks, 
without branches until after they have surpassed the trees around 
