Every Once in Awhile, It’s Easy

One thing or another has kept me away from botanizing in the past few weeks, but recently I did get out for a quick photo shoot along the Billy Goat C trail. I snapped a few pictures of this flower, recognizing it right aways as something in the Onagraceae (evening primrose family), and also knowing that I was probably setting myself up for failure, since identifying plants from photos never goes smoothly.

But this one did go smoothly. After just a few minutes with Weakley’s Flora I had it identified as Ludwigia decurrens (wingleaf primrose-willow). Then I checked with a few experts on-line, just to be sure, because there are no records for this species in the area where I found it.

Two weeks later I found another stand of it about a mile away from the first stand.

Wingleaf primrose-willow is listed S2S3 (state rare) in Maryland, and despite being rare in Indiana and endangered in Pennsylvania, it’s considered weedy by some authorities. It’s a wetland species that can grow to several feet tall. The winged leaves, stem, and capsule (seedpod) distinguish it from other species of Ludwigia; indeed, the specific epithet decurrens refers to this characteristic. (In botany, “decurrent” describes leaf tissue that continues along the stem below the node where the leaf attaches.)

A closely related species, Ludwigia alternifolia, has a similar looking flower, but lacks the decurrent leaves/stems. Also, the capsule is cube-shaped, a characteristic that gives the species its common name: seedbox [below right].


Most of the ten species of Ludwigia found in Maryland are plants of the Coastal Plain, but these two are also found in the Piedmont, along with two others, one of which, L. peploides (floating primrose-willow), I may have found earlier this summer [above left]. However, as the plants were in standing water in the C&O Canal, I couldn’t get close enough to make a positive identification. I couldn’t get close enough to get a decent picture, either. It’s possible that this is the alien species L. grandiflora, for which there are no records in the state of Maryland, but there are records for it in every surrounding state, so who knows.

Sand Dune Show

The Sonoran Desert’s wildflowers range from belly-flower sized to big and showy. Here are two of the latter. Although honestly, I took a lot of belly shots anyway. It was a sandy belly, sandy elbows kind of week.

Oenothera deltoides
dune evening primrose, desert evening primrose, birdcage evening primrose

There’s a native Oenothera species for every state in the Union except Alaska. Dune evening primrose is more widespread than many of them, and more widespread than many of the species I found in Anza-Borrego; it ranges from the Chihuahuan Desert north through the Sonoran and Mojave Deserts to the Great Basin Desert in Oregon, and also somewhat inland and along the California coast.

The plants I saw spread out along the sand maybe as much as three feet, and stood up to about a foot tall. I’ve read that in other parts of its range desert evening primrose can stand up to three feet tall. It’s described by various sources as both an annual and a perennial, so I’m not sure what to conclude there. One thing’s for sure, in Anza-Borrego at least it grows in association with this next plant. Almost any time I saw one, the other was there, too. Or close by.

Abronia villosa
desert sand verbena

Desert sand verbenas are not actually verbenas, which are in their own family. It’s in the four o’clock family (Nyctaginaceae). It is similar in size and growth habit to the dune evening primrose, but with a smaller range, being mostly restricted to the Sonoran and Mojave deserts, and some inland and coastal areas in California.

Take a look at the flowers. Looks like each has five petals, right? Not really. Another botanical oddity. More on that and other desert plants in the Nyctaginaceae next time.



There are at least six different species shown flowering in the first photo, and one plant not flowering but clearly a seventh species (not counting the dead ocotillo). Click on it to see it larger. This was one of the neat things about the super-bloom: so many different species growing together, forming crazy bouquets.


The willowherb family (Onagraceae) is large (about 650 species), cosmopolitan (represented just about everywhere), and taxonomically complicated (“relationships within the family have not been fully understood”*). So taxonomically complicated, it’s hard to even figure out what the current accepted botanical name is for this plant.


This first species, found near Akureyri in Iceland, has the common names broad-leaf fireweed, broad-leaved willowherb, arctic fireweed, dwarf fireweed, arctic river beauty, glacier rose, and who knows how many more. The Icelandic name is eyrarrós. The currently accepted botanical name (per ITIS) is Chamerion latifolium, but it’s also known as Chamaenerion latifolium and Epilobium latifolum.


Whatever you call it, it’s striking, standing about a foot tall, the blue-green leaves contrasting the rosy purple blossoms. It’s fairly common in Iceland, though with scattered distribution. It can also be found in higher latitudes around the northern hemisphere, and in mid-latitudes at high elevation (India, Pakistan, Nepal). In North America it’s present in Greenland, much of Canada, Alaska, and in mountainous parts of the West. A closely related species, Chamerion angustifolium, is found in parts of Maryland (as well as Iceland). And Nova Scotia, where I saw it two years ago.

There are about nine species of plants in the Onagraceae in Iceland, but I saw only two; this second species was near the glacier Sólheimajökull in the south of Iceland. It’s callled fjalladúnurt in Icelandic and alpine willowherb in English. It’s also called pimpernel willowherb, alpine willowweed, and dwarf fireweed. The accepted botanical name is Epilobium anagallidifolium. 

This species has an interesting split distribution in North America: in the east it’s found in Greenland, Quebec and a few of the Maritime provinces, New England, North Carolina, and Tennessee, then westward from the Rocky Mountains. (Note that BONAP does not show it present in the two southeastern US states.) It’s also found in northern Europe and northern Asia.

E. anagallidifolium is readily identified by the bent flowering stems (a harsh-weather adaptation according to NatureGate) and the dark red calyx.


Would you believe that I keep a detailed “life list” of my finds? No kidding. It’s arranged by plant family. Noted under Onagraceae are the two species in Iceland, two more in Nova Scotia, four in the Potomac gorge, and three in Death Valley.

I’m a botanerd.

One more thing, I can’t resist. Speaking of complicated, here’s a comically complicated explanation of Oenothera (the type species for this family):

  • Oenother’a: one source says that this name derives from the Greek oinos, “wine,” and thera, “to imbibe,” because an allied European plant was thought to induce a taste for wine. However, Stearn’s Dictionary of Plant Names gives an alternate meaning for thera as ‘booty,’ but also suggests that Oenothera could be a corruption of the Greek onotheras from onos, “ass,” and thera, “hunting, chase, pursuit” or ther, “wild beast.’ The root ther also can have the meaning of ‘summer.’ What this might have to do with the actual plant is unexplained. (ref. genus Oenothera)
    from calflora.net’s California Plant Names

*Wagner, W. L. and P. C. Hoch. 2005-. Onagraceae, The Evening Primrose Family website. http://botany.si.edu/onagraceae/index.cfm (July 28, 2016)

Two More Evening Primroses


brown-eyed evening-primrose
Chylismia claviformis ssp. claviformis
(right and below)




shredding evening-primrose
Eremothera boothii ssp.condensata



Both of these species in the Onagraceae are annuals found in various deserts of the American West. I spent some time trying to find interesting facts about them, but came up with very little. According to Pam Mackay’s Mojave Desert Wildflowers: A Field Guide to Wildflowers, Trees, and Shrubs, brown-eyed evening primrose has an extremely high photosynthetic rate. Also, the plant is favored by white-lined sphinx moth larvae, a fact that reminded me of a few photos I took of caterpillars, like this one:


There seems to be some morphological variation in these, so I’m not positive of the identification. But it was hanging around the brown-eyed evening primroses…


The Other Yellow Flower

On my second day in Death Valley, as I drove further north to slightly higher elevations, I noticed that the fields of gold had become fields of yellow.  The flowers looked different, too (as much as I could tell at 50 mph).  So of course I had to pull over and take a closer look.

The vast expanses of desert gold had become less-dense expanses of yellowcups, aka golden evening-primrose, Chylismia brevipes (formerly Camissonia brevipes; Onagraceae). They can stand nearly as tall as desert gold, but are generally shorter and more wispy in appearance. If you look closely you’ll see a tiny red dot at the base of each petal, an identifying characteristic of this species.

Yellowcups are native to the deserts of California, Nevada, Utah, and Arizona.