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from gardens to roadsides along the Atlantic coast and as far west as Iowa and Kansas.

Wormwood ((Artemisia biennis, Willd.).-An aromatic, somewhat bitter, smooth annual or biennial, from one to three feet high, with leafy stems and erect branches; lower leaves twice pinnately-parted, the upper pinnatifid, lobes linear or linear-oblong, serrate or cut-toothed; rayflowers absent; heads numerous in short axillary spikes; bracts of involucre green, scarious, margined. Common in the northern Mississippi Valley; now widely distributed east to Nova Scotia and south to Kentucky.

Western Mugwort (Artemisia Ludv, ciana, Nutt.).-A branching perennial; leaves and stems white woolly; leaves lanceolate, the upper usually entire, lower cut-toothed; heads in narrow panicles, rayflowers absent; involucre of dry and scarious scales; receptacle naked; flowers small, yellowish ; achenes obovoid; no pappus. Common on dry hills from Illinois north Fig. , ; ;. to Saskatchewan and southwest to Texas, Wormwood(ArColorado and Utah. The common mug- o: biennis).

- common weed wort of Europe (A. vulgaris) closely re- in the West and lated to the above species, has the lower North; (C. M. leaves glabrous above, white woolly be. ** g S apove, e Olly be

neath and pinnatifid; heads small in open panicles. Naturalized around dwellings eastward. The common sage brush of the West is A. tridentata. Absinth, A. absinthium, is shrubby and finely canescent; naturalized eastward.

Fireweed (Erechtites hieracifolia, (L.) Raf.).- An erect, coarse annual of rank odor and having a grooved stem, often hairy; leaves alternate, simple, lanceolate or oblong, acute, cut-toothed, the upper with auricled base; heads many flowered; receptacle hooked; flowers tubular and perfect; achenes oblong, tapering; pappus of copious, soft, white capillary bristles. Common in moist woods; in the North, also in recent clearings which have been burned over, hence the common name. From New England to Northwest Territory, Kansas, Louisiana and the southern Rockies. Burdock (Arctium Lappa, L.).-A coarse, branched, hairy biennial from one to three feet high; leaves large, roundish or heart-shaped, thin, obtuse, entire or dentate, tufted or matted with soft hairs on the under side; petioles deeply furrowed; bristles of the pappus unequal; native to Europe, common in gardens, fields and waste places in the northern states, but sometimes cultivated for its root, which is used in medicine. Bull Thistle (Cirsium lanceo l a tu m, (L.) Hill.). — A Fig. 156. Fireweed (Erech- branching perennial, three to tites Thieracifolia). Common in four feet high, covered with o: So,” * matted woolly hairs becoming dark green and villous with age; leaves lanceolate, decurrent on the stem with prickly wings deeply pinnatifid, the lobes with rigid, prickly points, the upper face roughened with short hairs, the lower, cottony; heads one and three-fourths to two inches high; bracts of the involucre lanceolate, rigid when young, more flexible with age; long attenuated, prickly pointed, spreading tips, woolly weblike; flower hermaphrodite, purple; achenes one and one-half inches long, pappus of numerous plumose bristles. This is a troubleSome weed along roadsides and in pastures, being most abundant in forest clearings; it has been naturalized from Europe. The seeds germinate in the spring, producing a mass of leaves; the second season, a flowering stem shoots rapidly up, producing flowers and seeds, then dies. Woolly Thistle (Cirsium canescens, Nutt.).A branching perennial two to four feet tall, woolly throughout, the branches bearing single medium sized heads; stem angled, white woolly; radical leaves, eight to twelve inches long, prominently ribbed, ending in stout spines, the divisions usually twolobed ; stem leaves, except the lower, one to four inches long, pinnatifid, the upper sessile, slightly roughened and Fig. 157. Burdock (Arctium I." "pa). covered with a slight Common in the North across the concottony down, the lower, tinent. (Clark-Hayden.) white woolly; heads one and one-half to two inches high, bracts of the involucre somewhat arachnoid, lower scales with a broad base, glutinous ridge, and ending in a minutely toothed spine, inner scales long attenuated, tips straw colored; flowers purple. Minnesota and western Iowa to the west and southwest. Prairie Thistle (Cirsium discolor, (Muhl.) Spreng.).A tall, branching, leafy biennial, five to seven feet high, with heads larger than those on the Canada thistle; stem grooved, slightly hirsute; radical leaves twelve to fourteen inches long, deeply pinnatifid, the divisions frequently divided, prickly toothed, the upper surface smoothish and the lower white and woolly, finely divided stem leaves; single heads one and one-half inches long with purple flowers terminating the branches; bracts of the involucre somewhat appressed, slightly weblike ; lower bracts ovate with a broad base and a weak, prickly, recurved bristle, slight dorsal gland; inner bracts, linear-lanceolate, with an entire, nearly colorless appendage; flowers purple, the lobes terminating in cleft tips; anther tips acute, filament pubescent; bristles of pappus plumose, achene smooth, upper part yellow. On roadsides and in meadows from New Brunswick westward to Ontario, Minnesota and Iowa. Canada Thistle (Cirsium arvense, (L.) Scop.).-A smooth perennial, spreading by creeping rootstocks; c or y m b o sely branched at the top, growing - - one to three feet high, smooth; - - , leaves lanceolate, sessile, and so o 6. deeply pinnatifid, the lobes and mon in pasture, , wood, lots margins of the leaves being be* (** set with spiny teeth; heads small, three-fourths to one inch high, bracts pressed closely to head, the outer with a broad base, the inner narrow, all with an acute, never spiny tip; flowers purple, dioecious; all the bristles of the pappus plumose. The chief points of difference between the Canada thistle and other allied species are as follows: the head is smaller, the involucre or modified leaves surrounding the head is not spiny, but smooth; the leaves are lance

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