The Euthamia Nuttall genus
The words or terms in red
(actually dark orange) in the text are defined in a
Euthamia, the Grass-leaved Goldenrod,
is a small genus of erect,
herbaceous perennials native
to North America.
The genus has nine eastern species
and one western species.
The genus was incorrectly included in the Solidago genus by many authors
for a more than a century although its morphology and leaf anatomy were
quite apart form the other members of the genus.
The plant belongs to the
Euthamia is still often listed in the Solidago genus;
Euthamia returned 19 700 results on Google while
Solidago returned 735 000 results!
studies as well as cpDNA RFLP
(Restriction Fragment Length Polymorphisms)
studies, showed that Euthamia
was phylogenetically not close to the true Goldenrods (Solidagos)
with a number of other genera more closely related.
These studies showed that the genus Solidago is related:
The Sericocarpus genus (the White-rayed Aster) is also related
to the Solidago genus.
But the Euthamia genus is not as closely related to the Solidago
genus as these genera.
- to the Chrysoma and Bigelowia genera,
native to the southeastern United States,
- to the Oreochrysum, Chrysothamnus, Petradoria, Tonestus and
Hesperadoria genera native to western North America.
All species of Euthamias have erect stems bearing linear
grass-like leaves with 1 to 7 well-developed veins and head borne in clusters.
The genus includes the following species:
- Euthamia caroliniana
- Euthamia galetorum
Euthamia graminifolia, photography above,
the only species found in Québec
- Euthamia gymnospermoides
- Euthamia hirtipes
- Euthamia leptocephala
- Euthamia occidentalis
- Euthamia pulverulenta
- Euthamia remota
In Greek, the adverb ευ
(eu) means well, regularly
(thameios) means numerous, frequent,
so that Euthamia would refer to the dense inflorescence of the genus.