Here's Pyxie!

Pyxie (Pyxidanthera barbulata), near Zuni, Va (3/16/19)

I was able to shout that on a recent weekend in southeast Virginia, but was certainly not the first to do so. That "honor" goes to Bayard Long in 1936.  Long was a botanist most associated with the Philadelphia Botanical Club, collector of approximately 80,000 plant specimens, and long-time friend and associate of Dr. M.L. Fernald (an account of Long's career, and publications, as well as the following image of Long, can be found in Rhodora 72:130-136)

Bayard Long was part of an infamous botanical collecting excursion near Franklin, Virginia that resulted in nine "new to Virginia" or state record plants being found.  Long was later quoted as saying, "this is real botanizing!" in the fascinating recount of the trip (Fernald, M.L. 1937, Rhodora 39: nos 465-468) (Also reprinted by Fernald in; Contributions from the Gray Herbarium of Harvard University, 1937, and selected excerpts included in Frost & Musselman 1987: Castanea 52:16-46.)



One wonders if Pyxidanthera would have gone unnoticed had it not been for Long.  In an earlier paper on the "Plants from the Outer Coastal Plain of Virginia" (Rhodora 38: nos. 455-466), Fernald credited Long as follows, "...with his detailed knowledge of Coastal Plain plants and their proper habitats and his unequalled (sic) persistence and skill in finding them, no critical botanizing in eastern Virginia can be wholly successful without him". 

In terms of the overall significance of their botanical finds, Fernald said, "We had stumbled into what we had sought for four years, real unspoiled pine barren in Virginia".

View of "mature" longleaf pines at Blackwater Ecological Preserve, VA
perhaps not unlike what Fernald and Long would have seen if they looked up!

Today, Fernald & Long's collecting site is protected and being actively managed as Blackwater Ecologic Preserve.  Longleaf pine (Pinus palustris) is a prominent tree in parts of the Preserve, which for Virginia, is really significant. At the extreme northern edge of it's natural range, the Commonwealth is believed to support fewer than 200 INDIVIDUAL mature, native longleaf pines (Virginia Department of Forestry 2014, Status Report).

Pyxidanthera range map; 
Kartesz, J.T., The Biota of North America Program (BONAP). 2015
Taxonomic Data Center. (http://www.bonap.net/tdc). 

But back to Pyxie (Pyxidanthera barbulata). Sometimes known as Pyxie-Moss or other related and confusing common names, Pyxie is restricted to the Atlantic Coastal Plain of eastern North America.
Sorrie and Weakley 2001 (Castanea 66:5-82) recognized Pyxie as a coastal plain endemic with a bimodal phytogeographic pattern, as shown to the left.




Pyxie's distribution has a large spatial disjunction that was significantly larger until Fernald's team found it in Virginia, or as they stated, "the first station discovered between southern New Jersey and North Carolina".  According to Fernald, "Pyxidanthera barbulata literally carpeted the ground in many areas".  The best approximation of that pattern I could see today, is shown on the image below, although at this distance (and due to my lack of photographic skill) the Pyxie clumps appear almost as bare "sugar sand".

Pyxie as an abundant ground cover at Blackwater Ecologic Preserve, VA

Pyxie covered by pine needles

Frost & Musselman used Pyxidanthera as a nominal in one of the community types they recognized at Blackwater in 1987 (See citation above), while noting it only"at this one spot".  They referred to this community as "Pond Pine Flat" with both Pond Pine (Pinus serotina) and Turkey Oak (Quercus laevis) as dominants and nominals.  Interestingly, in my experience, these species usually occur in fairly different habitats and soil moisture regimes.  Fernald referred to the habitat as "thin woods of Pinus taeda and Quercus laevis".  He indicated (with a footnote) that they found this oak "to be the regular species of the area" at its northern range limit.  Much like longleaf pine, this range limit has not been significantly extended northward since then.  Turkey Oak is still found at the site but is, perhaps, not as abundant as suggested by Frost & Musselman. (I hope to address this in detail in the future).

Turkey Oak (Quercus laevis) buds (3/16/19)

Turkey Oak (Quercus laevis) stump sprouts (3/16/19), approximately 2 years after last fire; note main trunk
broken off and fallen to right of image

Pond Pine (Pinus serotina) stump sprout, same site as previous;
also approximately 2 years since last fire; note main stem still standing but dead

Since 1986, there have been approximately 16 prescribed fires here with undoubtedly significant effects. 

Structural and density differences at Blackwater Ecologic Preserve
Right: burned on ~ 2 year average return interval since 1986
Left: unburned during same interval

For now, Pyxie seems to be doing just fine! 

Spring Scourge: Lesser Celandine (Ficaria verna)

Lesser Celandine in Richmond, VA (3/18/2018)

This Euroasian member of the Buttercup family (Ranunculaceae) has been introduced in North America since at least the 1860's. It hid under the radar in North Carolina until ~ 2005 (see Krings, Weakley, Neal, and Swab. 2005.  SIDA, Contributions to Botany 21(4):2429- 2437), but has now spread to at least 7 counties and likely more.

The distribution in Virginia is shown to the right; from the Digital Atlas of the Virginia Flora. (http://vaplantatlas.org)

The plant is becoming all to familiar to many of us.  According to Meghan Fellows, speaking about the Washington D.C. area, "Yes, it is getting worse. Floods and dispersal events spread this plant throughout our area. They are also extremely good at taking over new ground. Those pesky yellow carpets of weeds have replaced what should be a bounty of spring ephemerals (and their pollinators)." (https://www.lfwa.org/updates/tips-controlling-lesser-celandine). 

According to USDA APHIS, the species is now naturalized in 26 eastern states, as well as Oregon, Washington, and several provinces in Canada (See citation below). Calling large infestations "pesky yellow carpets" is an apt description that certainly applies to areas in and around Richmond, Virginia where I have seen the species (pictured below).   

Carpet of Lesser Celandine in  floodplain forest, Richmond, VA (04/10/2018)

There is some evidence these carpets are inevitable, once the plant becomes established.  They emerge on the forest floor in the late winter before other species leaf out and produce above-ground bulbils which greatly aid in dispersal (Verheyen & Hermy 2004. J. Veg Sci 15:125-134) 

 

Plants also develop extensive tubers that easily break off with mechanical disturbance and tend to survive many above ground treatment methods.

According to M. Fellows (cited above) the spreading carpets "are painful to watch - we want to DO something. Unfortunately, science has not kept up with our need. There is NO good, reliable way to kill celandine" (emphasis added). 

There is a relatively short window between the plant's emergence and senescence when control is possible. While I am convinced that control is possible, given enough dedication and commitment, thus far, I have not shown enough of either.  I have found little evidence of anyone else who has either, but am heartened and surprised by the efforts of some seemingly unlikely groups such as the Cleveland, Ohio Metroparks (see their herculean job described here): https://bugwoodcloud.org/mura/mipn/assets/File/Educational%20Resources/Lesser%20Celandine%20Control%20Program.pdf

For conspiracy theorists, I ran across this fascinating bit on the web: "And please dear listeners and readers, don't go around trying to wipe this plant out everywhere you see it because it's on some hit list.  It's not going to go away-and that "hit list" may well have been instigated by Monsanto or some other herbicide producer. Lesser celandine stabilizes wetland area brilliantly, and the buttercup-like flowers are breathtaking in the spring" (https://www.gardensalive.com/product/lesser-celandine for-some-a-bitter-buttercup) .....WOW!

Below I illustrate examples of how this plant moves and spreads.  Perhaps they start innocuously when a homeowner acquires the "breathtaking" plant from a website much like the one I just just cited. Soon the yard is engulfed and the mowing spreads the bulbils to the neighbors. From there plants wash into an adjoining drainage swale, and eventually run down-slope into the nearest creek, where overbank flooding pushes them into adjoining riparian forests. Invariably, these riparian areas are crisscrossed by sewer lines which need to be maintained by heavy equipment which disturbs the soil, spreads the tubers to the next job site......

Ficaria verna is this house's groundcover, note rosettes in the adjoining mowed lawn

Ficaria dominates this drainage swale in the same neighborhood as previous

The bright green, linear band is Ficaria  downstream from previous;
the wet woods in the background (one of Richmond's premier parks/natural areas)
have already been invaded.

Ficaria dominates both banks of the this creekside, uprooted clumps are found washed about

Water line a few feet above a tributary to the James River, 'Nuff Said?

In 2015, USDA APHIS considered the risks of spreads and predicted the following range for Lesser Celandine.

https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/wra/ficaria-verna.pdf

Breathtaking? Absolutely!

Irish Plant Carnivores

Round-leaved Sundew aka Common Sundew (Drosera rotundifolia), Killarney National Park. The leaves bear numerous modified stalks or "tentacles" tipped with clear droplets of sticky dew giving rise to the common name.

Not surprisingly, Charles Darwin made the first scientific study of carnivorous plants.  He began his 1875 pioneering work, entitled the "Insectivorous Plants", with a detailed examination of Drosera rotundifolia (pictured above).  Perhaps the most widespread of Ireland's 3 native Sundew (Drosera species), Darwin stated, "it was soon evident that Drosera was excellently adapted for the special purpose of catching insects." And further, "As this plant is extremely common in some districts, the number of insects thus annually slaughtered must be prodigious"!

All Sundew species included here (and studied by Darwin) share similar characteristics.  Each has leaves that appear reddish due to the presence of numerous stalked glands (or modified hairs). The stalks produce clear, sticky "dew".  The gland tipped stalks (which Darwin referred to as "tentacles") are typically longer and, perhaps, more concentrated on the leaf margins. Presumably this provides a larger trapping zone to aid in capturing prey. Much shorter stalks are found in the center of the leaves (see image below). Darwin found that stimulating a single tentacle (such as with a small piece of meat) caused it to bend inward, while the others nearby remained upright.  However, when the meat reached the leaf itself adjacent tentacles often "pour forth an increased amount of secretion" that becomes highly acidic.  Overall, Darwin believed, "the absorption of animal matter from captured insects explains how Drosera can flourish in extremely poor peaty soil".  

Round-leaved Sundew (Drosera rotundifolia) with digested prey remains at Bray Head, Ireland. The blackened insect remnants no longer produce enough stimulus to keep the tentacles pressing inward; according to Darwin these remnants will "be blown away by a breath of air" and the stalks will then re-secrete dew and be ready to clasp a new object once a new droplet of dew has formed. 

Drosera rotundifolia is the smallest of Ireland's sundews, and Great Sundew (Drosera anglica) is the largest. As the images below show, Great Sundew's leaves are much more elongated, to approximately 1" in  length, but share similar "tentacle" characteristics including the lengthier gland-tipped stalks around the margins, and reduced stalks mid-leaf. 

Great Sundew (Drosera anglica) with captured and partially digested prey. The longer stalks along the top of the leaf are bent downward and inward holding the prey, and bringing the item into contact with the smaller glands on the leaf front surface which are believed to produce digestive enzymes (See Lloyd, 1942, Carnivorous Plants). 

Great Sundew (Drosera anglica) with captured Mayfly. Unlike the previous image, the Mayfly is held against the back of the leaf, and digestion may not be possible due to the lack of necessary glands along this surface.

Great Sundew (Drosera anglica) - Note: back of leaf appears smooth & green, although minute glands are present barely visible to the naked eye. By far the longest and most well developed "tentacles" originate from the leaf margin where they aid in trapping.  

Great Sundew (Drosera anglica) has relatively large size and aggressive "tentacles" that, perhaps, enable it to catch larger prey items, such as the MayFly shown in the image above.  But in other respects, Darwin's study concluded that "the tentacles of Drosera anglica behave like those of Drosera rotundifolia."

The final of Ireland's 3 sundews is called Drosera intermedia. As the species name suggests, it lies between the other two in terms of leaf size, and shares characteristics of both species.  One trait thought to be indicative of Drosera intermedia is the branched, leafier stem, as shown in the image below. Assuming my ID is correct, nearly all individuals of this I observed were growing in open, shallow water "bog pools".  

Oblong-Leafed Sundew (Drosera intermedia), along Bog Road, Ireland

Patch of Oblong-Leafed Sundew (Drosera intermedia) in bog pool along Bog Road, Ireland

The second major group of carnivorous plants I include here are the Butterworts.

Butterworts (Pinguicula species) trap insects with "flypaper-like" basal leaves, which lie flat on the ground. There are 3 native, extant Butterwort species in Ireland. A 4th species, Alpine Butterwort (Pinguicula alpina), is considered extirpated, having not been found in Ireland since approximately 1912. I was lucky enough to see each of the extant species.

Butterwort leaves (presumably P. vulgaris) with partially digested prey items. All Pinguicula species share characteristic  compact, basal leaves like these, with some variation in size, and sometimes in color. They are invariably slightly incurved along the margins which Darwin believed helped prevent insects from being washed away by rainwater.

As the previous image shows, a number of different insects can be found attached to Pinguicula leaves. Darwin summarized numerous instances of insect capture on Pinguicula vulgaris (image below) and found that the glands secrete acid which "has the power of dissolving animal substances" and absorbing the result.  He said, "there can be no doubt that it profits by its power of digesting and absorbing matter from the prey which it habitually captures in such large numbers."  Interestingly, Darwin believed Pinguicula vulgaris also draws nourishment from pollen, leaves, and other plant parts adhering to its leaves, making it in part a "vegetable feeder."!

Large Flowered Butterwort (Pinguicula grandiflora), Killarney National Park, Ireland. In Darwin's time this species was considered a"sub-species" of P. vulgaris. 

Pale Butterowrt (Pinguicula lusitanica) near Bray Head, Ireland. The most different of the Irish Butterworts, with the much smaller almost transparent basal leaves and the pure white flowers.

Common Butterwort (Pinguicula vulgaris) near Famine Village, Ireland. I'm basing the tentative identification of this on the non-overlapping lower petals. 

A final look at Butterwort, this image taken near Caragh Lake, Ireland has a much paler petals than typical Large Flowered Butterwort.

You could spend your life searching for these species in their native habitats and it would not be a wasted life. 

For Peat's Sake: Turbary Rights & destruction of human created ecosystems?

I was lucky enough to be able to explore some very interesting habitats in western Ireland. Exactly what to call them, is unclear to me.  However, I believe the example shown above, could be referred to as a "Blanket Bog".  The Cottongrass (Eriophorum sp), drew me to the site, and initially suggested wetness (given my previous assumptions) but many examples I traipsed across were surprisingly dry.  The example shown below, was dramatically wetter, much more sphagnum moss was evident at the surface, pockets of almost open water were present, and the surface was really unstable and even dangerous to walk across. I think of this habitat as a "quaking bog".  In an upcoming post, I intend to show some of the interesting plant species I observed in both situations. From hereon, I lump both of these together as "peatlands" or bogs.

An example of early bog mapping in Ireland
(https://www.bordnamonalivinghistory.ie/maps/history-of-maps/)

The extent of Irish bogs was unknown until the early 1800's when a nationwide mapping effort began (image right) with the clear intention to make these areas more useful or productive.  But it wasn't until the 1930's, that Ireland's Department of Industry and Commerce began to actively plan for the development and use of these otherwise "worthless" landscapes.

A Turf Development Board was  established with the goal of developing a turf industry and operating & draining bogs. These efforts proved fortuitous during WWII, when turf became an essential alternative fuel source when coal imports were heavily diminished. Thousands of acres of bogs were eventually drained and actively harvested, sometimes with workers in on-site residential camps. Today at least one "semi-state" run corporation continues industrial-sale harvesting of peat , supplying an estimated 12% of Ireland's electricity  (https://www.sciencedirect.com/science/article/abs/pii/S0264837712000129).  This corporation just announced plans to cease all peat harvesting by 2028 (https://www.irishtimes.com/news/environment/bord-na-m%C3%B3na-not-climate-change-deniers-over-impact-of-peat-1.3696808)

In the meantime, turf cutting also continues for personal uses. The image below shows recently cut and stacked turf for use by a single family.

The right to take or cut turf is considered a "common right" or "turbary right" that involves a complex legal system that has led to many disputes.  The gentleman I spoke with about the operation above indicated his family had been cutting turf in this area (or exercising his turbary rights) for several generations. I came to see this much like a family woodlot maintained for cutting firewood in other areas of the world. Undoubtedly, dried peat or "turf" remains a primary fuel source for some Irish households. During my visit, it was not uncommon to smell peat fires burning in the morning and evening. I found published estimates of the number of households relying on turf ranging anywhere from 1 - 20% of Irish households.
(https://www.sciencedirect.com/science/article/abs/pii/S0264837712000129) (https://www.livescience.com/38498-ban-on-turf-cutting-peat.html)

I observed numerous "small scale" harvest operations, such as those above, with turf either being harvested or being laid to dry.  And then, I finally came to understand some of the unusual patterns I had been noticing and couldn't previously understand, in places where the harvest was not so recent. (see below).

Historic, subtle evidence of turf cutting near Caragh Lake, Ireland. 
Green arrows indicate approximate boundaries of former cuts

Historic evidence of turf cutting near Ballycroy National Park, Ireland.
Green arrows point to remnant former surface height

Most instances of both current and former harvest I observed were like those above, with regular harvest boundaries and harvest depths. Most also appeared to have more peat depth available to harvest in the future. However, a few other sites were very irregularly cut for reasons unclear to me, such as the deeply incised bog surface near Kerry, Ireland (note stacks of drying turf, and patches of Cottongrass, see below).

A few other examples had been extracted to depth exposing stump fields. These "stump fields" presumably represent woodlands that were destroyed by humans several thousand years ago.  Although the pattern of landscape change may vary locally, region-wide , "various evidences indicate that most of the areas now covered by blanket bog once carried woodland in the first half of the Holocene.  (http://www.paper.edu.cn/scholar/showpdf/NUz2ANxIMTD0YxeQh)

What caused the loss of the historic forests whose stumps are now exposed? 

According to the paper cited above (and numerous other sources), Neolithic farming & burning practices (between 4,000 - 5,000 years ago) were responsible for the initial decline and loss of woodland. This means early humans with stone tools (and fire) began extensively clearing forest. By the early Bronze age the job was essentially finished! 

Over the generations that followed, the bogs developed and blanketed over vast areas formerly occupied by forests.  In the end, "increased human activities" were the major cause of blanket bogs establishment! Thus, these bogs are "anthropogenic communities" created by the Irish ancestors.  I can't think of many other examples where a truly man-made vegetation type has become the object of conservation interest.

  

How much should we be concerned about  destroying something we previously created?

Taken by Ants in the Prairie Peninsula

Traipsing around in an open savanna under gnarled, seemingly ancient, Bur Oaks trees is like being in a little slice of heaven.  But why are these gigantic mounds of dirt lying about?  

"Solarium"  constructed by Allegheny Mound Ants, central Ohio

The denizens of these mounds quickly showed themselves; large two-colored ants, with red heads and thorax and  large black, shiny gaster or "metasoma".  Based on their appearance and distinctive mounds, I believe they were Allegheny Mound Ants (Formica exsectoides).  

Allegheny Mound Ants (presumably Formica exsectiodes), Crawford Co, Ohio 

Location of  Bur Oak savanna (bounded by the black box) amidst
active agriculture of central Ohio

The site is truly remarkable in the modern day landscape, and has been considered to be the "largest and best preserved remnant of the unplowed, deep soil prairies and savannahs that were present at the easternmost extension of the Prairie Peninsula prior to European settlement" (Mack & Boerner 2004, Castanea).

Bur Oak Savanna dominated by Quercus macrocarpa, Crawford County, Ohio.  

What ecological role could ants be serving in this habitat remnant?

Previously, at this site I had noticed ants clamoring on Sullivant's Milkweed (Asclepias sullivantii). Not being an ant taxonomist, I struggled with whether or not these were the same species as those from the nearby mounds. With the gracious assistance of Dr. Kaloyan Ivanov of the Virginia Museum of Natural History they are tentatively identified as Formica pallidefulva, not the Allegheny Mound Builders.  These ants seemed to be daintily sipping nectar from the flowers (see image below).  Could they be pollinating this prairie species?  

Ants (presumably Formica pallidefulva) sipping nectar from Sullivant's Milkweed in Bur Oak Savanna, Crawford County, Ohio. 

Perhaps, but after a bit of research I learned that ants rarely pollinate flowers.  More often than not, they simply steal nectar, and are often referred to as "nectar robbers".  For example, Wyatt (1980, Bulletin of Torrey Botanical Club) found that ants on a different milkweed species both reduced the amount of nectar available to butterflies and the overall effectiveness of the pollinators.  He termed ants "harmful to evolved pollination systems", and a "maladaptive force".   I looked at further images I had taken of the Sullivant's Milkweed with ants and noticed what appeared to be "maladaptive" behavior taken to a new level.  It appears that the ants were actively chewing away the flower structures, literally tearing open the stigmatic slit (where a pollinator leg would be expected to enter), impacting or even removing the ovary! (see image below).

Ants impacting Sullivant's Milkweed reproductive capacity(?);
arrow illustrates one example of torn flowers & ovary

Damaging milkweed!  Interrupting butterflies!  This behavior must stop! 

Although Allegheny Mound Ants weren't apparently responsible for the milkweed damage, much of  the readily available information on them involved recommendations like, "drenching a mound with liquid insecticide".  Michigan State Extension justifies doing so because, "the ants kill nearby vegetation including small tress and shrubs to keep shade off the mound. They do this by chewing a small hole in the bark and injecting formic acid into the wound" (http://msue.anr.msu.edu/news/mound_ants).  In contrast, Maine State Extension actually recommends ENCOURAGING their populations because the ant "plays a vital role....in a variety of ecosystems" (https://extension.umaine.edu/blueberries/factsheets/insects/195-allegheny-mound-ant/). 
Nice!

Henry McCook ~ 1877 with his beloved
Allegheny Mound Ants

Reverend Henry McCook (image left), was possibly the first and most careful observer of the Mound Ants. At one point he actually dug up an entire mound, frozen in the dead of winter, and transported it intact to the Academy of Natural Sciences in Philadelphia. His assumption that the colony "had gone down for winter-quarters into the deep galleries below the surface" was proven wrong when the mound thawed along with the "horde of hibernating ants within" which poured out all over the museum (1907, Nature's Craftsmen Popular Studies of Ants and other insects).     





In his earlier work, McCook (1877, Transactions American Entomological Society) described the most common size of mounds as 10-12 feet in circumference and 2.5 - 3 feet in height, but also mounds of tremendous size (over 6' in height and 50' in diameter). Andrews (1926, Pysche) suggested the Allegheny Mound Ants were the most common mound builder in North America,  ranging at least from Maine through Georgia.  However, he also suggested they were most often associated with places "left comparatively free from live stock and human interferences".  When encountered, mounds can be quite abundant. The incomparable Reverend McCook reported densities ranging from 25-59/acre.  My observations (see image below) suggest densities can be even higher in some locations.  High population densities, coupled with their reported tendency to kill nearby small trees and shrubs could certainly play a role in maintaining the open structure of prairies and savannas they inhabit.

Allegheny Mound Ant density, evident after prescribed fire, Daughmer Savanna, Ohio

Allegheny Mound Ant surfacing with soil aggregate
Adams County, Ohio

Overall, ants are probably the most consistent and important soil turning organisms worldwide (Tschinkle, 2015, PLoS ONE);
numerous papers describe their contributions to mixing, aerating, and altering nutrient dynamics of  soils they inhabit, and several document vegetation associations with mound ants (see Nemec, 2014, Journal of Insect Conservation).

Consider just the amount of surface area directly affected by the mounds in the image above. Baxter & Hole (1967, Proc. Soil Science Society Abstract, ) studied mound ants of a related species in a prairie remnant in southeastern Wisconsin. They showed the ants (which occupied 1.7% of the surface area) significantly altered the soil surface by bringing material upward and introducing organic material from their feeding habits. Overall, they believed the ants may be responsible for distinguishing the prairie soil from that of an adjacent and comparable forested area.

  In the end, it seems, the ants may create the prairie!