The More I Learn, the Less I Know

Readers of this blog will have noticed that I am fascinated by names. It isn’t enough for me to spot a plant and say “that’s a goldenrod”; I need to know which goldenrod, the actual species name, what other common names there might be for it and what the Latin words translate to and how it relates to other species… and pretty much anything else related to its taxonomy.

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No plant has led me into taxonomic Wonderland like this one —>.
I first saw it at Serpentine Barrens Conservation Park, in late August in bud, then in October in flower (kind of).

Right away I recognized it for a goldenrod, yet it looked a little different from other goldenrods. The flower heads weren’t in plumes or in the leaf axils like other goldenrods I know. So I took a few pictures, went home, and opened the books. It was easily categorized into “flat-topped goldenrods”, sometimes known as goldentops, for which Newcomb lists two Solidago species and Peterson lists four; Clemants and Gracie list two Euthamia species and two Oligoneuron species.

Hmm. Time to open more books.

Melanie Choukas-Bradley, in An Illustrated Guide to Eastern Woodland Wildflowers and Trees (2004), describes a lance-leaved goldenrod, Solidago graminifolia, noting that it’s also called Euthamia graminifolia, and also noting that “some botanists…consign the flat-topped goldenrods to a separate genus (Euthamia).”

Fleming, Lobstein, and Tufty, in Finding Wildflowers in the Washington-Baltimore Area (1995), report seeing “lance-leaved goldenrod (Solidago graminifolia)” in the area where I found this plant (they call the area the Potomac Power Line).

At this point I had tentatively decided that what I found and photographed would currently be called Euthamia graminifolia. I decided to run it by a few experts for confirmation. That’s when I learned that Euthamia is a “problem genus”.

Now I was really interested in learning what was going on, so I consulted a bunch of internet sources, and that’s when things got a little crazy.

In short, the USDA PLANTS Database lists six Euthamia species, not all of which are found in the Maryland Piedmont. BONAP lists five, only one of which is in the Piedmont. MBP lists four, only one of which is in the Piedmont. ITIS recognizes four species, and lists thirty-six Latin synonyms for E. graminifolia. Thirty-six!

Now totally confused, I consulted even more authorities, and found the following:

from EOL

 Euthamia is a genus of flowering plants in the aster family, Asteraceae.[2][3] They are known commonly as goldentops[4] and grass-leaved goldenrods.[5][6]

The species were formerly classed in genus Solidago, the goldenrods. They were separated on the basis of morphological differences, such as the arrangement of the flower heads in the inflorescence and the glands on the leaves, and of DNA data.[7] Authors have recognized 5 to 10 species.[5]

from the Astereae Lab:

Euthamia… is a small genus of erect, herbaceous perennials native to North America. Sierren (1981) revised the genus and recognized nine eastern species and one western species. Haines (2006 Flora North America) recognized only five species. Euthamia was incorrectly included in Solidago by many authors for a more than a century. Cronquist (1981) accepted the distinct generic status for this group of species on the basis of morphology and leaf anatomy (Anderson and Creech 1975).

Lane et al. (1996) showed that the on the bases of cpDNA, Euthamia was phylogenetically not close to the true goldenrods with a number of other genera more closely related…

Unfortunately, the practice of placing the grass-leaved goldenrods in Solidago continues and leads to errors in interpreting the results of ecological studies.

 

And finally, Flora of the Southern and Mid-Atlantic States (Alan S. Weakley, 2015) lists six species, with the note that Euthamia is

A genus of about 8-10 species, herbs, of North America. There are a number of serious problems remaining in our knowledge of Euthamia.

Apparently so.

Weakley’s key is excellent, and if I can get back to the park before the plant is done blooming, I might be able to key it out. Stay tuned…

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on-line sources

USDA PLANTS Database
BONAP (The Biota of North America Program)
MBP (Maryland Biodiversity Project)
ITIS (Integrated Taxonomic Information System)
EOL (Encyclopedia of Life)
Astereae Lab (University of Waterloo)
Weakley Flora (The University of North Carolina Herbarium)

2 thoughts on “The More I Learn, the Less I Know

  1. > the-more-i-learn-the-less-i-know
    Homo sapien nescius
    (tentative ID, conflicting sources list unconfirmable synonyms and symptoms)

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