Solidago spp.; goldenrod [Asteraceae]  Several dozen species of rhizomatous perennials with stature varying by species.  Small pale yellow to golden flowers, either in curved, one-sided clusters as the name suggests, or in a variety of other arrangements.  Leaves simple, usually toothed, but otherwise varying in shape and size both by species and by position on the stem.  Most grow in open ground, specific habitat depending on the species; almost all flower in late summer or fall.  [139]