taxonomy | Elizabeth's Wildflower Blog

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.

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…

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)

marginal wood fern
Dryopteris marginalis

This summer I took an Audubon Naturalist Society class on ferns and lycophytes. You’re probably wondering, “what is a lycophyte?” Hang tight, I’ll get to that.

Apparently I’m not the only wildflower enthusiast to keep a log or life list of finds; turns out I’m also not the only one who includes ferns on that list, though ferns aren’t even flowering plants.

So what does that mean, “ferns aren’t even flowering plants”?

that kind of looks like a flower spike, but it isn’t; it’s the fertile (spore-bearing) stalk of a rattlesnake fern, Botrypus virginianus

If you recall from grade school science, the taxonomic hierarchy starts with the plant and animal kingdoms, then moves down to division (phylum for animals), class, order, family, genus, and finally species.

Flowering plants are in the class Magnoliopsida. They are vascular (containing tissues that transport fluids and nutrients), and reproduce via seeds. Ferns are in a different class: Polypodiopsida. They are also vascular plants, but they reproduce via spores. Lycophtyes are in a third class, Lycopodiopsida; like ferns, they are vascular and reproduce via spores, but the morphology is different: ferns consist of rhizomes with roots below and fronds above, while lycophytes have stems with roots and tiny, scale-like leaves (called microphylls) that cover the stem above ground.

Ferns and lycophytes have differing evolutionary lineages as well, but I’ll spare you the details.

The current state of taxonomy is way different from what we learned in grade school. It gets complicated because there are different systems and the scientific community doesn’t seem to be in agreement about which one best fits our current understanding of evolutionary history. For anyone who’s interested, here’s a little detour.

One widely used system (Woese) starts with domain, of which there are three; kingdoms are the next step down. The differentiation is rather technical, but the domains are named Archaea, Bacteria, and Eukaryota. The plant kingdom (Plantae) is in the last of these.

ITIS (the Integrated Taxonomic Information System, one of the more authoritative sources) has adopted a seven-kingdom system as its standard. The kingdoms are Bacteria, Protozoa, Plantae, Fungi, Animalia, Chromista, and Archaea.

A google search on the phrase “kingdoms of life” will show other systems, dividing life into five or six kingdoms.

In ITIS, the next levels below kingdom are more divided than in the old KDCOFGS system. If you go down the tree looking for ferns and lycophytes , you’ll see below the plant kingdom two subkingdoms; the one containing ferns is divided into two infrakingdoms; one of those is composed of two superdivisions; then after that come the divisions, of which there are eight. Ferns and lycophytes are in the Tracheophyta (vascular plants).

Ignoring the three subdivisions, there are seven classes within the division Tracheophyta:

Cycadopsida: cycads (seed plants that vaguely resemble palms)
Ginkgoopsida: ginko (Gingko biloba, all by itself way up here in the taxonomic hierarchy!)
Gnetopsida: three genera of woody plants resembling conifers
Pinopsida: conifers (non-flowering, seed-bearing plants)
Magnoliopsida: flowering, seed-bearing plants
Lycopodiopsida: clubmosses, firmosses, spikemosses, quillworts
Polypodiopsida: ferns

Older field guides and text books refer to certain plants as “fern allies” or “fern relatives”. These include the clubmosses, firmosses, ground cedars, horsetails, scouring rushes, quillworts, and a few others. Of those, horsetails and whisk ferns are now considered to be true ferns. The rest are considered lycophytes. All of this reclassification is quite recent and based on molecular phylogenetic studies.

The point I’m trying to make, other than taxonomy is messed-up but fascinating, is that ferns and lycophtyes are only distantly related to the flowering plants I usually write about. But they are abundant, beautiful, and interesting, so I’ll be posting about them.

a lycophyte, commonly called “ground pine”, generally known as a “clubmoss”, but it isn’t in the same class as pines, and isn’t in the same division as mosses!

Next time, a look at fern morphology and nomenclature.

Elizabeth's Wildflower Blog

hunting in the Maryland piedmont (mostly)

Tag Archives: taxonomy

The More I Learn, the Less I Know

Ferns and Lycophytes: an Introduction