Goldenrods are a ubiquitous part of late summer and fall, and for such prolific plants they are remarkably underappreciated and poorly known. Most of our thinking about them is tainted by the super-abundant Canada Goldenrod, Solidago canadensis, which is THE goldenrod of old fields, often growing in association with New England Aster, Symphyotrichum novae-angliae.
Just as with birds or anything else, it's a good idea to really nail down the ID of the common and widespread species first. This is one of them; Elm-leaved Goldenrod, Solidago ulmifolia. It is a common species of dry woodland borders and open woods, and is a rather spindly plant with racemes of tiny flowers. Ulmifolia means "elm-leaved" (Ulmus is the genus of elms), and that's really what the leaves resemble. Elm-leaved Goldenrod typically grows in profusion where it occurs, forming little herbaceous thickets.
This is another common goldenrod and I'll guarantee you've noticed it. It's Gray Goldenrod, Solidago nemoralis, one of our smallest species. This individual is particularly luxuriant; normally it has but a single raceme of yellow flowers, and the raceme always droops or bends towards the tip. Gray Goldenrod is very much a plant of dry barren ground, and often is only a foot or so tall. Watch for it along the Interstates; it is the goldenrod that forms colonies on the mostly barren soil of roadbanks.This one's a beaut, and one of Ohio's rarest species. It is Leafy Goldenrod, Solidago squarrosa, and this population is the only currently known in southern Ohio. I discovered it on this remote roadbank in Shawnee about a dozen years ago, and it is still doing well. Leafy Goldenrod is one of our most robust species, and some plants reach four feet in height. The flowers are also huge, at least in relation to many goldenrods. It is quite showy, and would make a nice ornamental although I don't think the gardening community is yet bold enough to embrace goldenrods. Squarrosa refers to the phyllaries; the tiny leaf-like bracts that subtend the flowers. Squarrose means "recurved" and if you look closely you can see the phyllaries below the flowers spreading outwards and curved back. No other Ohio goldenrod looks like this.
Here's a view looking down the stem of a young Leafy Goldenrod. The leaves get progressively larger downwards, and the basal (lowest) leaves are downright enormous. This species grows on dry, shaly banks.Ah, the confusing fall warblers of the goldenrod world - the wand-like species! Goldenrods, generally speaking, come in three arrangements: corymbose (flat-topped flowers); thyrsoid or paniculate (the Canada Goldenrod type of plumes); and wand-like (the beast above). Some of the wand-like species seem unstable in regards to species relationships and species lines perhaps blur together, at least here and there. This seems to be the case in Shawnee. The one above looks to me most like Erect Goldenrod, Solidago erecta, but there are problems. Two other species of "wands" occur in the forest and it may be that there is hybridization going on between the "species" - they need more study. Whatever it is, it is quite showy.
A closeup of the flowers. This colony of Erect Goldenrod was growing on a very dry, rocky slope that supports many other interesting plants. The stunning Yellow-fringed Orchid, Platanthera ciliaris, grows nearby, and at least four other species of goldenrods were companions. In all, I saw ten species of goldenrods over the weekend and could have added a few more had I been after the "Goldenrod Big Day" record, which is probably ripe for the plucking.