They continue in great beauty all summer and autumn, and in 
early winter they show symptoms of weakness or decay ; but, 
with a little care, plenty of young plants may be retained for 
the followmg spring, when they soon revive and reproduce 
by offsets. The flowers, or inflorescence, are nestled at the base 
of the leaf, and it may easily be seen there, by some of the 
young unfolded leaves, that the spatha which encloses the flowers 
is nothing but a modified leaf, the lower sides involute, and 
bearmg the stamens and pistil. These flowers possess no 
beauty. The roots are a very pretty object on a plant being 
lifted out of the water, for here, as in the Duckweed (Lemua) 
of our own country—and Pis/ia is sometimes called tropical 
Duckweed,—the roots descend loose into the water, with no 
necessary attachment to soil or mud, and are long and feathery. 
Like many water-plants, it has a very extended range, perhaps 
all round the world, in tropical or subtropical regions. In 
America it extends as far north as Louisiana and Mississippi 
and North Carolina. From Africa, I possess specimens from 
Egypt in the north, from the Niger country near the middle, 
and from Port Natal in the south. In the warm parts of India 
it seems to be universal; and in the Malay Islands. In Antigua, 
of the West Indies, Patrick Brown tells us it is most abundant 
in all the ponds of water preserved for public use, and keeps 
the water always fresh and cool, which would be greatly subject 
to putrefaction and charged with a multitude of insects, had 
they continued exposed to the heat of the sun. ‘The plant, 
however, is. there considered acrid, and when the droughts set in 
and the waters are reduced very low (which frequently happens 
in that island), they are overheated and so impregnated with the 
particles of this vegetable, that they occasion bloody fluxes to 
such as are obliged to use them at those seasons. 
I am aware that some botanists are disposed to consider that 
there are several distinct species of Pistia, and Professor Kunth 
goes so far as to constitute two groupes, and of one groupe to 
make two subgroupes, including altogether no less than zine 
species: but the characters are wretchedly defined, and I must 
confess, that as far as can be collected from the dried state of 
the copious specimens in my herbarium, there is no reason for 
constituting more than one species. Others, however, must 
judge for themselves. Our plant here figured is derived from 
_ Jamaica, and quite accords with Roxburgh’s from the Hast 
Indies ;—yet Sloane’s Jamaica species (Hist. t. 2. f. 2) is re- 
ferred by Kunth to his P. commutata, and Brown’s Jamaica 
plant to P. obcordata. 
Descr. Each plant sends down a tuft of long, soft, feathery 
fibres, and consists of a collection of rosulate /eaves, which are 
