. An illustrated flora of the northern United States, Canada and the British possessions, from Newfoundland to the parallel of the southern boundary of Virginia, and from the Atlantic Ocean westward to the 102d meridian. Botany; Botany. Richweed. Wild hemp. Horse-weed. 2. Ambrosia trifida L. Horse-cane. Bitter- weed. Great Ragweed. Fig. 4126. Ambrosia trifida L. Sp. PI. 987. 1753. A. integrifolia Muhl.; Willd. Sp. PI. 4: 375. 1805. Ambrosia trifida integrifolia T. & G. Fl. N. A. 2: 290. 1841. Annual, scabrous or hispid, or nearly glabrous, branched, 3°-i7° high. Leaves all opposite, petiol
. An illustrated flora of the northern United States, Canada and the British possessions, from Newfoundland to the parallel of the southern boundary of Virginia, and from the Atlantic Ocean westward to the 102d meridian. Botany; Botany. Richweed. Wild hemp. Horse-weed. 2. Ambrosia trifida L. Horse-cane. Bitter- weed. Great Ragweed. Fig. 4126. Ambrosia trifida L. Sp. PI. 987. 1753. A. integrifolia Muhl.; Willd. Sp. PI. 4: 375. 1805. Ambrosia trifida integrifolia T. & G. Fl. N. A. 2: 290. 1841. Annual, scabrous or hispid, or nearly glabrous, branched, 3°-i7° high. Leaves all opposite, petioled, 3-nerved, deeply 3-5-lobed, or undivided, the lobes lanceolate or ovate, serrate, acute or acuminate; lower leaves often ic wide; racemes of sterile heads 3'-io' long, their involucres saucer-shaped, 3-ribbed on the outer side, crenate-margined or truncate, their receptacles naked; fertile heads usually clustered in the axils of the upper bract-like leaves, turbinate to obovoid, 5-7-ribbed, conic-beaked, 3"-4" long, each rib bearing a tubercle near the summit. In moist soil, Quebec to Florida, west to Manitoba, Nebraska, Colorado and New Mexico. Tall ambrosia. Buffalo-weed. Hay-fever weed. July-Oct. 3. Ambrosia elatior L. Ragweed. Roman Wormwood. Hogweed. Wild Tansy. Fig. 4127. Ambrosia elatior L. Sp. PI. 987. 1753. Ambrosia artemisiaefolia L. Sp. PI. 988. 1753. Annual, pubescent, puberulent or hirsute, panicu- lately branched, i°-6° high. Leaves thin, 1-2-pin- natifid, petioled, 2'-4' long, the upper alternate, the lower mostly opposite,- pale or canescent beneath, the lobes oblong or lanceolate, obtuse or acute; uppermost leaves of the branches sometimes linear- lanceolate and entire; racemes of sterile heads very numerous, i'-6' long, the involucres hemispheric, crenate, the receptacle chaffy; fertile heads obovoid or subglobose, mostly clustered, 1V-2" long, short- beaked, 4-6-spined near the summit, sparingly pu- bescent. In dry soil, often a pernici
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1913
