A specimen of the limosella (with some specimens of the tillea) was sent to Z. Collins, Esq. of Philadelphia, who wrote me that Mr. Nuttall had found the same plant, a few days previous to the receipt of my letter, and that they had no question on the subject of the generic character, but that it would probably prove to be a new species. In the transactions of the Medico-Physical Society of New-York, page 440, it is described under the name of limosella subulata. A description of the plant was published about the same time, by Mr. Nuttall, in the Journal of the Academy of Natural Sciences of Philadelphia. (See Vol. I. No. 6. p. 115.) In the paper written by Mr. Nuttall is the following query: "Does this plant, with a lateral mode of growth and alternate leaves, germinate with two cotyledons?" The following observations were made in answer to this question. In the winter of 1816-17 this plant was kept in a situation exposed to severe frost; yet whenever the weather became warm for two or three days, it became quite green, but for the last winter there was no appearance of life in the plant. In March 1818, the vessel in which the limosella had been preserved for two summers preceding, and in which were a great quantity of seeds, was exposed in a warm situation to the sun. There was no appearance of vegetation until the last of March, when were observed several cylindrical leaves, some of them evidently arose from bulbs which had formed the last summer, on account of the dryness of its situation, which frequently occurs when plants are removed from a moist to a dry situation. In other instances single cylindrical leaves arose from the earth, where no bulbs were to be found; these cylindrical leaves were thought to arise from seeds, which, if it was a fact, would prove that the plant vegetated with but one cotyledon. In a short time the vessel was crowded with the seeds of the limosella raised by the cotyledons. These were carefully observed, and in every instance, when the coat of the seed was cast off, two linear cotyledons were observed, soon a cylindrical leaf arose from the centre of the cotyledons, and when this leaf had grown to the length of half an inch, a leaf of a similar kind arose laterally to a line made by the first leaf and the cotyledons. From the facts above stated, it is thought to be proved that the limosella vegetates with two cotyledons. This was the fact in every instance where the husk of the seeds was obviously attached to the cotyledons, and in the few instances where the plants appeared to vegetate with but one cotyledon, it is probable that it arose from a bulb or some portion of the old plant, in which life had not been extinguished, during the past winter, which was made more probable by the fact that several of the leaves arose obviously from bulbs. This limosella,[11] with its congeners, hence will take its place in the natural order of Jussieu lysimachiæ.