MONOECIA DIANDRIA. 
519 
I wish here merely to notice a variety or species of this genus which many 
years ago I was accustomed to see floating on the surface of the ponds 
around Beaufort. The fronds were rather larger than those of the L. Minor, 
and were so attached near one of the foci of the ellipse as to form constantly 
segments of circles. I do not recollect that I ever saw a circle completed, 
though I could not discover what stopped or terminated its progress. 
Found in ponds, ditches, and stagnant waters, commonly called “Duck 
Weed/’ and considered as a favourite food of many species of the wild 
duck. The insects which are sheltered by these plants, however, are more 
probably the food which these birds so eagerly seek. 
Flowers July — August? 
2. PoLYRHIZA, 
L. foliis ellipticis, 
planis; basi cohaeren- 
tibus; radicibus fasci- 
culatis. 
Leaves elliptic, flat, 
cohering at base; roots 
clustered. 
Sp. pi. 4. p. 195. Pursh, 1. p. 22. 
Fronds larger than those of the preceding species, convex and dark purple 
underneath. Roots clustered. 
Flowers July — August? 
This very obscure genus, whose flowers it is so uncommon to find, has 
lately been examined with great care by Dr. Hooker of Glasgow. It appears 
in the Linnsean system to belong to the class Piandria, and its fructification 
to consist of a single flower composed of an urceolate, membranaceous, mo- 
nophyllous perianth, from a small opening in the top of which the stigma is 
protruded, and which bursts irregularly as the stamens become developed. 
These are two in number, (rarely wanting.) Anthers of two rounded lobes, 
opening nearly vertically each into two valves. Germen roundish, com- 
pressed, carinated on one side, tapering into a style about its own length, 
and terminated by a flattish stigma. Fruit an utriculus transversely oblong, 
compressed, emarginate at the top on which is the short persistent style. 
Seed one, (or more?) very hard, oval, lying horizontally in the utriculus and 
fixed by its lower sides. Embryo oblong, monocotyledonous, horizontal, 
central, surrounded by a whitish, fleshy albumen. 
Dr. Hooker supported by R. Brown, considers this genus as standing next 
to Pistia in the natural order of the aroideae. In order, however, to give it 
this, its proper location, we must consider the perianth as a spath and the 
spadix as a point bearing two naked flowers, the upper male and diandrous, 
the inferior female, and the genus will then stand as it now generally does, 
among the monoecious plants. 
