1. Euthamia graminifolia (L.) Nutt. (common flat-topped goldenrod)
Solidago
graminifolia (L.)
Salisb.
S.
graminifolia var. nuttallii
(Greene) Fernald
E.
graminifolia var. nuttallii
(Greene) W. Stone
Pl. 234 g–i; Map
979
Stems 40–120 cm
long, sparsely pubescent with minute, spreading hairs, at least toward the tip.
Leaf blades 1–12 cm long, 1–10 mm wide, relatively thick, the margins
moderately roughened with minute, stout, ascending, stiff hairs, the surfaces
glabrous or sparsely pubescent with minute, spreading hairs, moderately resinous
with impressed or pustular glandular dots, the smaller leaves with 1 midvein,
the larger leaves with 3 or occasionally 5 main veins. Involucre 3–5 mm long,
relatively resinous, the bracts variously rounded to sharply pointed at the
tip. Ray florets 15–25(–35), the corollas 1–2 mm long, the short ligule
ascending. Disc florets 4–10(–13), the corolla 1.5–2.0 mm long, the lobes 0.3–0.7
mm long. 2n=18. August–October.
Uncommon, mostly
in counties bordering the Missouri River (northern U.S. south to Wyoming,
Oklahoma, and Georgia; Canada; introduced in Europe, Asia). Loess hill
prairies, savannas, and bottomland forests; also roadsides.
The present
treatment differs markedly from that of Steyermark (1963). Steyermark treated E.
graminifolia (as Solidago) with two varieties, basing his treatment
on earlier taxonomic studies summarized in Fernald (1950). He excluded the
glabrous var. graminifolia from the Missouri flora but accepted a
larger-headed variant with somewhat hairy leaves and stems as S.
graminifolia var. nuttallii and a smaller-headed variant with leaves
only minutely roughened along the margins as S. graminifolia var. media
(Greene) S.K. Harris. He reported populations of var. nuttallii as
occurring uncommonly in a few counties along the Missouri River, with var. media
widespread in the state. Since that time, Missouri botanists have had great
difficulty in using this treatment to distinguish the latter variety from E.
gymnospermoides, as it turns out with just cause. Croat (1970) studied a
number of morphological characters throughout the range of the two taxa and
observed widespread intergradation between S. graminifolia and S.
gymnospermoides var. media. Subsequently, Sieren (1970, 1981)
studied plants of the complex in the field and herbarium from Illinois and
Wisconsin west into the Great Plains. His research confirmed that plants
previously treated as S. graminifolia var. media were better
included within E. gymnospermoides and also that there was too much
intergradation between different morphotypes within that species to allow
formal recognition of varieties within that species.
Within E.
graminifolia, Sieren (1970, 1981) accepted three strongly intergrading
varieties, with the hairy, robust var. nuttallii perhaps the most distinctive
element in the species. Missouri specimens are less hairy than those from the
main portion of the range, and some authors (Cronquist, 1991) have questioned
whether the variety is consistently distinguishable. The glabrous taxa var. graminifolia
and var. major (Michx.) Moldenke supposedly differ from one another
primarily in the length-to-width ratio of the larger leaves, and both occur
mainly to the north of Missouri. Because these variants overlap considerably
and do not seem to have much ecological or geographic separation, there seems
little point in recognizing them.