=Range and habitat.=—This weed has been introduced from Europe and occurs in stony, uncultivated localities and waste places in the Southern States and in California and Utah. [Illustration: FIG. 23.—Blessed thistle (_Cnicus benedictus_ L.).] =Description.=—Blessed thistle is an annual plant belonging to the aster family (Asteraceæ). The round stems are erect, about 1 to 2 feet high, branched, and rather woolly. The leaves are more or less hairy, the lower ones borne on petioles (leaf stems), the upper ones sessile (stemless) and clasping the stem. They are oblong-lanceolate and wavy-lobed. The terminal yellow flower heads are surrounded by scales of a leathery texture, which are prolonged into long, hard, branching spines. =Parts used.=—The leaves and tops should be collected when the plant is in flower, about June, thoroughly and quickly dried, and kept in a vessel from which moisture, light, and air should be excluded. They have a somewhat disagreeable odor and the taste is very bitter. Blessed thistle is employed in fevers, dyspepsia, and as a tonic to restore the appetite. =Imports and prices.=—This plant is cultivated in Germany, from which country it is imported to a limited extent. The price per pound ranges from 8 to 10 cents. YARROW. _Achillea millefolium_ L. [Illustration: FIG. 24.—Yarrow (_Achillea millefolium_ L.).] =Other common names.=—Milfoil, thousand leaf, thousand-leaved clover, green arrow, gordoloba, nosebleed, bloodwort, carpenter’s grass, sanguinary, soldiers’ woundwort, old man’s pepper. (Fig. 24.) =Range and habitat.=—This herb is a common weed from the New England States to Missouri and in scattered localities in other parts of the country, occurring along roadsides, in old fields, pastures, and meadows. =Description.=—Yarrow is a perennial belonging to the aster family (Asteraceæ). It is about 10 to 20 inches in height, its numerous dark-green feathery leaves divided into very fine crowded parts. The flowers are produced in abundance from June to September. These are small, white (sometimes rose-colored), and are crowded in dense flat-topped heads. The odor of yarrow is strong and aromatic, very similar to that of chamomile, and the taste is sharp and bitter. When this plant is eaten by cows its bitter taste and strong odor are imparted to dairy products. =Parts used.=—The entire plant is collected when in flower, and is carefully dried. The coarser stems should be rejected. The plant loses nearly four-fifths of its weight in drying. Yarrow is a stimulant tonic, acts upon the bladder, and checks excessive discharges. =Imports and prices.=—This is an imported article, though not brought into the United States in large quantities. The price of achillea or yarrow ranges from 2 to 5 cents per pound. CANADA FLEABANE. _Leptilon canadense_ (L.) Britton. (_Erigeron canadensis_ L.)