. 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 102nd meridian. the branches prostrate orcreeping, J°-2° long. Leaves ovate, oval or rhombic, i-ilong, usually acute, serrate-dentate above the middle, cu-neate at the base; peduncles shorter than the subtendingleaves; involucre campanulate. the bracts broadly ovate,obtuse, l-! long, imiformly prickly: disk-flowers withcorollas l long, puberulent; mature inner bracts of theinvolucre forming
. 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 102nd meridian. the branches prostrate orcreeping, J°-2° long. Leaves ovate, oval or rhombic, i-ilong, usually acute, serrate-dentate above the middle, cu-neate at the base; peduncles shorter than the subtendingleaves; involucre campanulate. the bracts broadly ovate,obtuse, l-! long, imiformly prickly: disk-flowers withcorollas l long, puberulent; mature inner bracts of theinvolucre forming a starfish-like bur, each lobe 4-$ long,densely beset with uniform blunt weak prickles. In waste places and dry soil. Virginia to Florida and Louisi-ana. June-Oct. Widely distributed as a weed in tropical re-gions. 51. SILPHIUM L. Sp. PI. 919. T753. Tall perennial herbs, with resinous juice, opposite whorlcd or alternate leaves, and large•corymbose or paniculate (rarely solitary) peduncled heads of both tubular and radiate yellowflowers. Involucre hemispheric or campanulate. its bracts imbricated in few series. Recep-tacle flat or nearly so, chaffy, the chaff subtending the disk-flowers. Ray-flowers in 2 or 3. 460 COMPOSITAE. Vol. III. series, pistillate, fertile, the ligules numerous, linear. Disk-flowers perfect but sterile, theircorollas tubular, 5-toothed, the style undivided. Anthers minutely 2-toothed or entire at thebase. Achenes broad, dorsally flattened, 2-winged, notched at the apex. Pappus none, or of2 awns confluent with the wings of the achene. [Greek, from the resinous juice.] About 12 species, natives of North America, known as Rosin-weed or Rosin-plant. Type species:Silphium Asteriscus L. Stem leafy, the leaves opposite, alternate, or verticillate. Leaves, or their petiole-bases, connate-perfoliate; stem not connate-perfoliate, sessile or petioled. Leaves opposite, or the uppermost ahernate ; cauline sessile. Leaves, or some of them, verticilla
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1913
