January 24.th, i8gg7\ Proceedings. ix 



meadow-land, and, it is affirmed, to stop the progress of boats 

 and even steamers. In Louisiana similar disasters have occurred : 

 the climate seemed exactly to suit the plant, and Government 

 aid had at last to be invoked, and steam-dredgers used to extir- 

 pate it. This was very difficult, for if even a small piece of 

 the matted roots was left, fresh offshoots would rapidly grow, and 

 flower the first season. Indeed, in the Bayou St. John in the 

 same state (Louisiana), no means have been found effectual 

 to stop its incursions, where once it has obtained a footing. 

 The timber industry was threatened, as rafts could not be sent 

 down the river. Grand Lake, not far off the Bayou, has likewise 

 been invaded. This vast expanse of water, forty-five miles long by 

 an average of six broad, is in parts already like a wide meadow, 

 spangled with most beautiful purple hyacinth-like flowers. Cold 

 weather alone seems to stop its increase, and it then sinks to the 

 bottom of the river, but, with the approach of warm weather, 

 rises again and propagates very rapidly. 



Eichhornia Kunth, Enum. PI., iv. 129 (1843) is a small 

 genus of the Nat. Ord. PontederiacecB, containing about seven 

 species, all natives of tropical America, except one W. African. 

 The four genera composing this small order, viz., Pontederia L., 

 Eichhornia Kunth, Heteranthera R. and P. (inclusive of SchoUera 

 Schreb.) and Monochoria Presl, are all much alike, possessing 

 spikes of hermaphrodite flowers in most instances, often very 

 regular. Perianth usually six-lobed, stamens varying from three 

 to six, unequally fixed to the base of the segments, filaments 

 free, filiform. Anthers oblong. Style filiform or columnar. 

 Fruit loculicidally dehiscent, dividing its three valves with a 

 membranaceous pericarp. Ovary free as a rule, 3-celled, ovules 

 anatropal. The flowers are spathaceous, leaves sheathing cordate 

 or sagittate, with inflated petioles. Species about 33, Pontederia 

 being all American, Eichhornia (as already mentioned) American 

 and W. African, Heteranthera the same, and Monochoria entirely 

 of the Old World, one species, M. vaginalis, being of very wide 

 distribution. 



If we consider the strict law of priority, the name Eichhornia 



