Look at the Sweet Phyllaries on that One!

A look at the disk and ray florets of Symphyotrichum patens (late fall aster)

A lot of folks don’t seem to like attempting to identify plants in the Asteraceae family, more commonly known as the asters. This is a very large family of plants and there are definitely many difficult cases out there in terms of identifying. However, with a good dichotomous key, a hand lens and some patience, I think most anyone can have success in learning some of these interesting plants. The key is learning what characteristics are “key.” The group I am featuring here are three members of the Symphyotrichum genus, often referred to as the “new world asters.” Following recent taxonomic revisions, the genus now holds more than 100 species, of which about 25 can be found in Missouri. Most ray flowers are light blue to violet but some can be white or pink as well.

Photographs can be useful when attempting to identify the new world asters. These can be referred to when attempting identification on your own or sending to someone with more expertise on the group. Knowing what to photograph is important.

A good look at the distinctive involucre of Symphyotrichum patens.

First, both sides of the flower, referred to as the capitulum (composite inflorescence) in the asters, is important in making an identification. Photograph the ray and disk florets along with the involucre from the underside should be photographed. The involucre is a protective structure composed of a group of phyllaries (bracts) that can be beneficial in discerning between species. Asters in this group can be distinguished from one another by the number of ray florets per capitulum and the size of the flowerheads 

The growth habit of Symphyotrichum patens.

Two other photographs you will want to take when attempting to ID the Symphyotrichum are of the plant’s growth habit and the leaves – particularly details of how the leaves are attached to the stems. There are usually key differences here that will be useful when making an identification. Unfortunately, I neglected to take closeups of the leaves while working with these three plants in the front yard this past autumn.

The next species I would like to feature is the spectacular Symphyotrichum oblongifolium, or “aromatic aster.” These plants are quite impressive. Pinch them back once sometime in the month of June and they will bush out, forming impressive globes of violet blooms. The accompanying habit photos are from our front bed and is only three plants! Although these plants create enormous amounts of blooms, I find that it is almost too late in the year. Most of the blooms don’t open until well into October. During this time, most of the pollinators that visited these blooms were honey bees, at least in my yard. I think most of the native pollinators had finished their season by this point.

The above images show the growth habit at flowering of Symphyotrichum oblongifolium.

I hope the next couple of images exemplifies how the phyllaries are important diagnostically for identifying these plants whose flowers look very similar when viewed head-on.

The capitulum of Symphyotrichum oblongifolium. Notice how strikingly different the involucre is compared to S. pattens.

The straw-colored disk flowers of Symphyotrichum drummondii will turn maroon to purple in color late in the season.
Symphyotrichum drummondii – named after Scottish botanist Thomas Drummond, who spent time in St. Louis prior to his famous plant collecting trip to Texas in the 1830s.

Finally, the third member of this genus I have tried in the front yard beds is Symphyotrichum drummondii (Drummond’s aster). This one looks a lot different from the other two, not only in the characteristics of the capitulum, but in its growth habit as well. This is much more of a small, dainty plant that is found in open woodlands and savannahs in the northern sections of Missouri.

A look at the narrow and widely-spaced phyllaries of Symphyotrichum drummondii.

When Splitting is a Good Thing (Spiranthes niklasii)

Anyone who has hung around biologists and naturalists long enough has surely heard the complaints of how taxonomists are going too far in their evil over-splitting ways. Their notion being that phylogenies painstakingly developed via decades of phenotypic comparisons should not be overturned by a few afternoons of running gels in a lab. I’m sure most of us can point to a convincing example of over-splitting amongst our favorite groups of organisms, but I hope that the subject that I am featuring tonight will give you pause before reaching for that familiar defense and realize there are circumstances where a group benefits from a fine dissection when the appropriate tools are available.

A great example of a group that has benefited from a well-executed genetic taxonomic treatment is the Spiranthes cernua species complex of the “ladies tresses” orchids. This species complex has long been known for cryptic species with curious cases of plants being plants – exhibiting hybridism, polyploidy (having more than two sets of chromosomes) and apomixis (reproduction without fertilization). The species, Spiranthes cernua, which is found in Missouri, has been problematic and considered as a polyphyletic taxa (derived from two or more distinct ancestral taxa). In attempting to shed light on the phylogenetics of this species complex, Mathew Pace and Kenneth Cameron have published a fantastic treatment in which they attempt at “Untangling the Gordian Knot”. Most of what I write here is paraphrased from their paper cited at the end of this post.

Spiranthes niklasii – an ancient case of kissing cousins in the Ouachita Mountains.

A common method of speciation in plants is interspecific hybridization. Pace and Cameron identified three instances of ancient hybrid speciation involving S. cernua. One of these circumstances that has now been given specific status is Spiranthes niklasii. This species is near-endemic to the Ouachita Mountains of Arkansas and is likely a result of a proposed ancient hybridization event between Spiranthes cernua and Spiranthes ovalis.

Pace and Cameron describe S. niklasii as being quite similar in appearance to S. cernua, but can be distinguished by “a central ridge of small papillae on the adaxial surface of the labellum, more strongly campanulate flowers, and usual preference for a more xeric habitat.” When I read this and found out we had an opportunity to see this species, I knew I wanted to try and capture those papillae in a photograph. We found this species in bloom in Saline and Pulaski Counties in Arkansas on 10, October, 2021. While my photos cannot do justice to the excellent figures found in the above mentioned work, I was still thrilled to be able to capture these minute structures while on a camping trip in the Ouachitas.

The ridge of papillae on the labellum of this flower, as seen above, is a diagnostic trait of Spiranthes niklasii.

By the way, one of the other cases of hybrid speciation involving S. cernua that was identified by Pace and Cameron has further implications on my work. Spiranthes incurva is a newly described species that is hypothesized to be the result of an ancient hybridization between Spiranthes cernua and Spiranthes magnicamporum. In Missouri, the result of this split is that S. incurva now lies roughly above the Missouri River while S. cernua is found south of the river. This means that I now have added another species to my orchids of Missouri. A new orchid for me to photograph!

I would like to thank Casey Galvin and Eric Hunt for helping me find these plants.

Literature Cited

Pace, Mathew C., and Cameron, Kenneth M. 2017. The systematics of Spiranthes cernua species complex (Orchidaceae): Untangling the Gordian Knot. Systematic Botany. 42(4): pp. 1-30

Until next time,
-Ozark Bill

Fruits of Fall

Tonight I’m sharing a couple of fascinating fruits that Pete and found on a late October hike from last year. Both of these plants are in the bittersweet (Celastraceae) family.

First up is Euonymus atropurpureus, or the eastern wahoo. This is a relative of the strawberry bush but is much more widespread across the state. I put one of these in the yard this past fall and am hoping it will establish itself. Like the strawberry bush, this fruit will split in autumn or winter, exposing four scarlet seeds.

Fruits of Euonymus atropurpureus (eastern wahoo). Photographed on 21/OCT/2021 in St. Francois County, MO.

Next up is Celastrus scandens (American bittersweet), a twinning woody vine that sometimes behaves as a bush. Pete and I enjoyed a few of these sweet, intensely-red fruits. Thankfully, we did not enjoy too many as I read afterwards that these are mildly toxic if eaten. Neither of us felt any ill effects afterwards.

Fruits of Celastrus scandens (American bittersweet). Photographed on 27/OCT/2021 in St. Francois County, MO.

-Ozark Bill

Crystallofolia – A Return To Missouri’s Autumn “Frost Flowers”

I first posted about frost flowers a little more than ten years ago on this blog. This season, after learning about the two plants that are most likely to form them in our geography and having the flexibility to be on location at the specific times they are capable of forming, I was able to take advantage and take my time in capturing them with the camera.

The first gallery are the more robust of the crystallofolia. Dave and I stumbled across these in Madison County, MO. These are formed on the dying stalks of Verbesina virginica (F. Asteraceae), aptly named “frostweed” or white crownbeard. This is the more robust plant of the two featured here and, consequently, forms larger and more robust frost flowers. Some of these were up to 12″ in height.

A note about how crystallofolia form.
Because these later-maturing species are still somewhat viable during the first deep freeze, the xylem pathways responsible for moving water from the roots to the shoots are still functional. The roots in the still unfrozen soils are pushing water to the shoot of the plant via capillary action. On the first few nights when temperatures drop to the mid 20 degrees F, the water in the shoot freezes, bursting the sides of the stem pushing the freezing water out and forms these gorgeous petals. If you look closely, you can see the individual “tubes” of ice that make up the petals of the frost flowers. These tubes correspond directly to the xylem rays – the tubes that distribute water from the vertical rising xylem to the outer tissues of the plant. Another interesting thing about these structures is that they will often dissipate through sublimation. The super cold and dry conditions can cause these thin and delicate petals to evaporate directly to gas, skipping the liquid water phase.

The second species featured here were found in Jefferson County, MO on a trail. Earlier in the season I had noted the abundance of dittany (Cunila origanoides) F. Lamiaceae. This species is smaller and forms dainty frost flowers, mostly no more than four inches in height. They can also be much more elaborate than the frost flowers formed by V. virginica, with long, curling petals that have a tendency to curl back on themselves.

From the Home Garden – Oenothera macrocarpa (Ozark Sundrop)

I know this is a well-known plant for those of us who care about such things, but I can’t believe it isn’t more popular than it is. For the most part, it gets along pretty well with much of our soils (I’m hoping it will stick around in our yard despite the fact that its growing in a mostly clay bed), needs no watering, is easy to propagate and is a perennial! You will typically see this plant listed as “Missouri evening primrose”. However, I recently read it referred to as “Ozark sundrop” and thought that was just perfect.

Oenothera macrocarpa (Ozark Sundrop) grown in my front yard bed.

Anyway, I was pleasantly surprised that the couple of potted plants I put in the ground last spring decide to bloom in their first year. I know the flowers last but a day, but I don’t have to tell you how much they’re worth seeing when they bloom right outside your front door. Check these out in the wild too. They grow in great numbers at a couple of glade spots in Jefferson County – Valley View Glades and Victoria Glades – along with a lot of other fantastic species that bloom at the same time.

Spiranthes ovalis – Another Look

Spiranthes ovalis erostella. This variety of S. ovalis is primarily self-pollinated, hence the weak and withered flowers.

Pete and I had both seen Spiranthes ovalis erostella prior to this outing in late September in Pope County, IL, but we both agreed that this was the finest specimen we had seen of what is usually a small and insignificant plant with a puny inflorescence.

Spiranthes ovalis (lesser ladies’ tresses orchid) is typically found in open, woody habitat and particularly likes areas where disturbance has limited competition and opened access to light.

Euonymus americanus (Strawberry Bush)

Euonymus americanus in bloom. Strawberry bush usually blooms in mid to late May in MO. This species can be difficult to distinguish from the other bushy Euonymus in the area, including the invasive Euonymus alatus (burning bush). When not in bloom, E. americanus is the only bushy Euonymus that has five petals, all the remaining having four.

Ranked as an S2 (imperiled) species of conservation concern in Missouri, Euonymus americanus is a striking plant in more than one season. Where it grows in the Show Me State it is always threatened by white-tailed deer who absolutely love our native Euonymus spp. In areas with overpopulation of deer, the plant has been removed from the landscape. This past autumn, I planted one in the fenced-in portion of our backyard in the remaining humus and decay of an old ash stump. I’m hoping the soil here will be rich enough for its liking and that the deer will not discover it.

The unique and unmistakable fruits that give strawberry bush its name. This plant was found in Butler County, MO.