Comparative study on morphological characteristics of "Huang-ying-hua", invasive alien weed Solidago canadensis L. and its relatives with the same genus.
"Huang-ying-hua" is a widely-used cut flower in florist currently, but it is similar to the invasive weed Solidago canadensis in morphological characteristics, so it has caused public concerns. Comparative studies on morphological characteristics of eight batches of "Huang-ying-hua" with 35 invasive populations of S. canadensis in our country, two populations of Solidago L. sampled from Canada and Solidago decurrens were conducted. The cluster analysis showed that seven batches of "Huang-ying-hua" samples were clustered together except the fifth batch, which was clustered with S. canadensis in one group, "Huang-ying-hua", S. canadensis, and the populations sampled in Canada were clustered into one group while S. decurrens was grouped into sole one. This showed "Huang-ying-hua" is similar to S. canadensis, not S. decurrens. The further comparative studies on morphological of S. gigantea and S. altissima showed that "Huang-ying-hua" and S. altissima were together and clustered with invasive populations, and the populations sampled from Canada were more similar to S. gigantea. S. canadensis, S. altissima and S. gigantea all belonged to S. canadensis complex. The length/width ratio of leaves, the length between triplinerved and leaf base, the number of epidermal hair on vein and the ratio of disc florets to ray florets were the important morphological characteristics of "Huang-ying-hua" and other species in genus of Solidago L.