hazardous to impeach a popular tradition; but it appears much more likely that they were brought over in some of the first grass-seed that came from England. Both plants are perennial, spreading rapidly from the root, and propagating with equal facility from the seed. These abundant powers of reproduction meeting with a genial soil and a loose husbandry, it is no wonder that they should produce the effects so obvious in our neighborhood. The white-weed belongs to that class of plants whose seeds are often furnished with feathery appendages, like the dandelion, thistle, and many others; a race of wanderers that traverse the earth with astonishing rapidity.
Next to the wood-wax and white-weed, the knap-weed (Centaurea nigra) deserves attention. This plant, of recent introduction from Europe, is making rapid advances in our neighborhood. It should be pointed out to our farmers, who ought by all means to resist its invasion. It is a most villanous weed, utterly unfit for fodder, whether green or dry. It is sometimes called the thistle without thorns; but it will prove a thorn in the sides of some of our husbandmen, difficult of expulsion, if it is suffered to continue its advances. It propagates by creeping roots and feathery seeds, much after the manner of the white-weed.
Of all the plants that threaten the agriculturalist, perhaps none is more formidable than the Canada thistle (Cnicus arvensis), which has probably reached us from the great Western prairies. This plant is known to every one: it forms extensive beds by the road-sides, and frequently in the pastures. The hard, gravelly soil of this vicinity is not very favorable to its growth. It loves a rich loam, through which it can send its runners with ease and facility. Mr. Curtis, an English gentleman, in order to test the astonishing powers of reproduction possessed by this plant, deposited about two inches of a root in his garden. In the course of one summer, it had thrown out, under ground, runners on every side: some of these runners were eight feet long; and some of them had thrown up leaves eight feet from the original root. The whole together, when taken up and washed, weighed four pounds. In the spring following, it made its appearance,
