Dr. A. Gattinger, of Nashville, says: "A few days ago, while paying some attention to the autumnal flora, I happened to pass by a small pond on Mrs. Spence's place, near the Lebanon pike, and to observe the ' Wolffia Columbiana,' a plant of such diminutive size that rarely any one would notice it except a botanist, aware of its existence and eager to find it. The surface of the pool is covered with a green scum, which, at a close inspection, is found to consist of two distinct little plants. The one, a flat and disk-shaped, roundish, floating frond, the size of a lentil, with a few delicate rootlets pending from the lower surface, is the 'Lemna polyrrhiza,' a species of Duckweed. The other looks like very small green grains, scattered between the Duckweed, and forming with this a dense covering over the entire pool. These grains are oval-shaped, measuring from1 /8 to 1/3 of a line in length, floating half submersed, and void of rootlets. It is very rarely seen in flower, its general way of propagating being by bulblets, produced at the edge of the frond, and falling to the bottom of the water at maturity.

The flower, where it happens to be found, is proportionate in dimensions, almost invisible to the naked eye, and consists of one stamen and one pistil, which burst through a chink in the upper surface of the small frond, and produce one ovule".