662. WATER-HEMLOCK. Phellandrium aquaticum.--Linnaeus informs us that the horses in Sweden by eating of this plant are seized with a kind of palsy, which he supposes is brought upon them, not so much by any noxious qualities in the plant itself, as by a certain insect which breeds in the stalks, called by him for that reason Curculio paraplecticus [Syst. Nat. 510]. The Swedes give swine's dung for the cure. 663. YEW. Taxus baccata.--This is poisonous to cattle: farmers and other persons should be careful of this being thrown where sheep or cattle feed in snowy weather. It is particularly dangerous to deer, for they will eat of it with avidity when it comes in their way. * * * * * SECTION XV.--PLANTS NOXIOUS IN AGRICULTURE. Annual Weeds, or such as grow wild in Fields, and that do not produce any Food for Cattle. Many weeds are troublesome to the farmer amongst his crops; but which, by affording a little fodder at some season or other, in some degree compensate for their intrusion. But as the following are not of this description, they ought at all times to be extirpated: for it should be recollected, that the space occupied by such a plant would, in many instances, afford room for many ears of wheat, &c. The following are annuals, and chiefly grow among arable crops, as corn, &c. As these every year spring up from seeds, it is a very difficult matter for the farmer to prevent their increase, especially since the practice of fallowing land has become almost obsolete. It is a fact worthy notice, that the seeds of most of the annual weeds will lie in the ground for many years, if they happen to be place deep: so that all land is more or less impregnated with them, and a fresh supply is produced every time the land is ploughed. It is therefore proper that annual weeds of every description should be prevented as much as possible can be from going to seed, for one year's crop will take several seasons to eradicate. The only effectual mode we are acquainted with of getting rid of annual weeds is, either by hoeing them up when young, or by cutting the plants over with any instrument whilst in bloom; for it should be observed, that those never spring from the roots if cut over at that period of their growth, which oftentimes may be easily accomplished.