Flora of the Hawaiian Islands
Literature for Conyza canadensis
Wagner et al., 1990, 1999.
   Asteraceae -- The Sunflower Family Bibliography
      Conyza canadensis
General Information
DistributionNative from southern Canada and the United States south to tropical America, widely naturalized.
Plants green, 1-15 dm tall, unbranched or nearly so to the inflorescence, glabrous to coarsely hirsute.
Leaves numerous, oblanceolate to linear, those of the central half of the stem 4-10 cm long, 0.3-0.6 cm wide, the basal ones deciduous and broader, becoming progressively reduced above, margins entire to toothed.
Heads usually numerous; involucre 3-4 mm high, bracts sometimes purple-tipped, glabrous or with a few small scattered hairs; ray florets 25-40 per head, female, rays 0.5-1 mm long; pappus yellowish to yellowish brown, in a single series, somewhat longer than the inner florets.
2n = 9, 18, 32, 54