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 m 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. POLYRIIIZA. 



L. foliis ellipticis, | Leaves elliptic^ flat^ 

 planis; basi cohaeren- cohering at basej roots 

 tibus; radicibus fasci- clustered, 

 culatis. I 



Sp. pi. 4. p. 195. Pursh, 1. p, 22. 



Fronds larger than those of the preceding species, convex and dark purple 

 underneath. Roofs 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 Linnaean system to belong to the class Diandria, and its fructification 

 to consist of a single flower composed of an urceolate, membranaceous, mo- 

 xiophyllous 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 titriadus transversely oblong, 

 compressed, emarglnate at the top on which is the short persistent style. 

 ^eed one, (or more?) very hard, oval, lying horizontally in the utriculus and 

 fi^ed by its lower sides. Enibryo oblong, raonocotyledonous, 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 mferior female, and the genus* will then stand as it now generally does, 

 among the monoecious plants. ^ 



