Wednesday, May 16, 2018

A most marked new plant & reverse nyctinasty?

Kate's Mountain Clover (Trifolium virginicum) with inflorescence and  horizontal leaves in shaded portion of shale barren
Douthat State Park, VA (May 13, 2018)

Kate's Mountain Clover (Trifolium virginicum) was first discovered during a plant collecting trip to "southwestern Virginia" by famed botanist J.K Small in 1892.  Observed on the rocky slopes of Kate's Mountain, Greenbrier County, West Virginia, Small's published account (1893, Memoirs of the Torrey Botanical Club) indicated this species to be "the most marked new plant collected on the expedition", and distinct from all other eastern American species.  Today, we recognize the global range of Kate's Mountain Clover extending across the Valley & Ridge region of VA, WV, MD, and PA as shown on the map below.

Trifolium virginicum range,

A 1908 botanical monograph on North American Clovers by McDermott lumped Small's Clover with Trifolium reflexum and suggested that the species was "abundant throughout the Appalachian Mountains".  Small's opinion on this treatment was documented by Hunnewell in a brief note entitled, "A new station for three local Appalachian Plants" (Rhodora, 1923). Small was quoted as follows, "to say that the species is common in the Appalachian Mountains, may be prophecy, but such a statement certainly cannot be backed by good evidence".

Prophetic or not, many botanists have focused their attention on Trifolium virginicum since then. At one time or another, all Natural Heritage Programs within the natural range have tracked the species. Collectively, the species has been assigned a "G3 or vulnerable" rank by NatureServe. The West Virginia Native Plant Society is justifiably proud of both the plant and its discovery and has adopted the species as their official symbol. Kate's Mountain Clover has also been considered the "flagship species of the shale barrens" (Maryland Botanical Heritage Working Group, 2014).

Shale Barren habitat @ Douthat State Park, VA

Although Small did not refer to the habitat for his collection as a "shale barren" (the term did not come into common usage until approximately 1911), there are well known shale barrens on Kate's Mountain and some authors have indicated Trifolium virginicum as a shale barren endemic (Braunschweig, Nilsen & Wiebolt 1999).  The species has since been rarely encountered on related habitats, but is still most often associated with shale barrens (see 

The typical shale barren habitat is a harsh environment for plant growth. The surface is often unstable with loose rock fragments and minimal soil development & the typically steep slopes tend to shed any litter accumulation down slope where it accumulates at the toe slopes (See images below).

Shale barren fractured rock surface consisting of thousands of "channers"

Toe slope of shale barren/woodland;
green line roughly indicates boundary of litter accumulation  

According to Braunschweig, Nilsen & Wiebolt (1999), surface soil temperatures and high solar irradiance distinguish shale barrens from non-shale barren sites. It has been suggested that air temperatures on the barrens are comparable to the desert regions of North America and several sources indicate soil surface temperatures at shale barrens throughout the mid-Appalachians routinely reach 50-60 degrees Celsius, or 120 degrees Farenheit.

However, such conditions do not prelude seedlings from establishing. I noticed many areas of exposed channery literally carpeted with seedlings (see image below), although I fully expect most of these seedlings to eventually succumb thereby maintaining the relatively open aspect typical of share barrens.
Exposed shale surface with abundant seedlings

What allows a species like Trifolium virginicum to adapt to the harsh environmental conditions of shale barrens?  Apparently noone really knows!  However, Clovers (Trifolium spp.) are generally known to exhibit "nyctinasty", a fancy word for plant movement caused by a stimulus, and others think of this as "sleep movement."  J. W. Harshberger devoted at least 15 years to the study of clovers and devised a contraption to measure the nyctinastic movements of various species (He published his work in the Proceedings of the American Philosophical Society, 1922). Charles Darwin also studied this phenomenon and wrote an entire book entitled "Power of Movement in Plants" in which he detailed many examples of nyctinasty. A classic example of this movement would be drooping leaves in the evening that open again in the morning, presumably to capture sunlight. However, Trifolium growing in extreme situations of high irradiance and surface temperature may need to do the opposite.  Widening and unfurling leaflets in midday would expose them to potentially dangerous heat levels. Compare the image at the top of this post taken mere moments before the image below. The former plant occurred in a patch of shade and had fully unfurled leaves/leaflets; the plant below shows vertically upright leaves in a sunnier and much hotter location.

Kate's Mountain Clover (Trifolium virginicumwith inflorescence and mostly vertical leaves in open shale barren
Douthat State Park, Bath County, VA (May 13, 2018)

I've got to go back to do more field research!

View from shale barren@Douthat State Park

Friday, April 27, 2018

Prairie Goldenrod & Its Unusual Habitats

Prairie Goldenrod (Oligoneuron album) doesn't look like your typical "goldenrod".  But it was once considered a member of the genus Solidago, lending some scientific basis to calling it a goldenrod. To some it is still referred to as Solidago ptarmicoides. This plant has been kicked around taxonomically an almost shocking number of times. But I digress....

Prairie Goldenrod is a legitimate rarity in North Carolina, and is either absent from or rare in most other southeastern states. Why in the world doesn't it occur in Virginia?

The apparent rarity or absence from much of the southeast may not be surprising since it is presumably PRAIRIE Goldenrod and relatively few such habitats occur in the region.  However, one site, perhaps the only extant site in North Carolina, is both botanically rich and very much "prairie-like".

Prairie-like habitat of Oligoneuron album in Granville Co, North Carolina; note faint white specks of Oligoneuron stems in flower., see inset below

Closer view of Oligoneuron album in Prairie-like habitat,in North Carolina; flanked by the basal rosettes of Prairie Dock. (9/18/2013)

The North Carolina site discussed here also includes abundant Prairie Dock (Silphium terebinthinaceum), Stiff Goldenrod (Solidago rigida) and many other species often associated with prairies elsewhere in the country.  This site may be as close to true prairie as it can get in NC and is certainly one of the only known locations resembling a prairie with reasonably intact vegetation on a soil typical of prairie. Broadly, most of the North American Prairie region is closely tied to the occurrence of Mollisols (see map below).

Soil from the North Carolina Oligoneuron "prairie" site,
classified by soil scientists as a Mollisol.
The dark color is one the characteristics of this soil order.

USDA Soil Map, Mollisols

It is hard to overstate how unusual this soil is in Carolina.  As the generalized USDA soil map shows, there are no mapped Mollisols of sufficient extent to appear on the map almost anywhere in the southeastern US outside Florida.  A retired University Soil Scientist once told me it took years for the existence of these soils to be accepted in North Carolina, even having the "dirt in hand", since historical convention suggested such soils couldn't develop in the North Carolina climate.  But again, I digress......

This post was supposed to be about Prairie Goldenrod.

Oligoneuerun album apparently thriving in remnant tallgrass prairies in Paintbrush Prairie, Missouri.(08/17/2015)
Rattlesnake Master (Eryngium yuccifolium) is barely visible as well.

Prairie Goldenrod does actually occur in undeniably classic "tallgrass prairies" in the midwestern US, which some refer to as the Central Tallgrass region.  I have observed it in several tallgrass prairie remnants in Missouri such as that shown above.

Taken together, my admittedly few observations seem to fit into a nice and tidy picture of the habitat for Prairie Goldenrod.

But, then I visited alvars along Lake Huron in Ontario Canada.

I was absolutely shocked to find Prairie Goldenrod on lakeshore pavements (on exposed rock I believe is dolomite), and even in loose sandy soil at the margins of Lake Huron!.  These were NOT PRAIRIES.

Prairie Goldenrod on alvar,lakeshore pavement, Misery Bay

Prairie Goldenrod along Lake Huron, Ontario Canada
I did finally find Prairie Goldenrod in one habitat much more akin to prairie near Lake Huron. Much of the ground surface was littered with small boulders that are likely glacial erratics. The matrix soil was primarily sand that apparently washed in under extreme tides or storm events, covering the underlying dolomite flat rock. Such disturbance events, coupled with the underlying pavement, help keep the habitat from becoming overgrown by shrubs and trees. The most visually dominant herb, other than Prairie Goldenrod was Limestone Calamint (Calamintha arkansana). 

Prairie Goldenrod amidst glacial erratics and loose sand near Lake Huron, 

Interestingly, NatureServe uses Oligoneuron album as a nominal in one of its described alvar natural community types, but rather than it being used to name a "grassland" type it is considered part of a shrubland:


No matter what habitat seems to support Prairie Goldenrod they are all well worth the look!

Sunday, March 18, 2018

Great Lakes Alvars

One of the interesting, mostly open aspect, natural community groups of eastern North America are the so-called "alvars" of the Great Lakes region. Concentrated in Ontario Canada where these images were taken, alvars include a range of  natural communities. Like many similar habitats in eastern North America they stand in striking contrast to the surrounding, often densely forested landscape. In the image below, these forests consist largely of Jack Pine (Pinus banksiana) and Northern White Cedar (Thuja occidentalis).

Alvar  Inland Pavement - dominated by non-vascular plants, primarily tussock mosses, Bruce Peninsula

It has been shown that the majority of known alvars occur with  approximately 1 km of shorelines (  Many authors, especially Catling and Brownell, 1995 and 1999, distinguish shoreline alvars from those occurring in more interior locations.  The most notable difference between these is the sparseness of the vegetation on shoreline or coastal examples (see images below).

Alvar  Coastal Pavement - sparse to very sparse plant cover, Bruce Peninsula

Alvar  Coastal Pavement - inundated by low water levels and wave actions, Bruce Peninsula

Lobelia kalmii in shoreline alvar@Misery Bay

Fringed Gentian (Gentianopsis sp) in shoreline alvar@Misery Bay

However, Catling and Brownell (1999) also list several plant species indicative of both types. Among their list of species "more or less restricted to shoreline alvars" is Kalm's Lobelia (image, right). Although not included on their list, I noticed fringed gentians (image, below left) only in shoreline alvars as well. 

All North American alvars are restricted to  limestone or dolomite in the Great Lakes region (see map below), stripped of surface material by glaciation action. Several examples I observed  had glacial erratics present. 

Alvar Distribution:

Inland alvar pavement with glacial erratics, Misery Bay

The extent of vegetation cover across alvars is highly variable; NatureServe recognizes at least 13 different natural communities with different structure and composition. 

Inland alvar with very shallow soil, superficially dominated
 by Limestone Calamint (Clinopodium arkansanum), 6/17/17

Limestone Calamint, formerly Calamintha arkansana, was considered a dominant species on Lake Huron alvars according to Catling and Brownell (1999). This appeared to be the case in several examples I saw as well especially in very shallow soils around open inland pavements; NatureServe includes it as a nominal in one of their community types as well.

(Right: Limestone Calamint (Clinopodium arkansanum); 6/17/17)

Only one of the NatureServe described types is considered "sparse", much like the image at 
the top of this page. The majority of the remaining community types are considered grasslands
or shrublands (See NatureServe Explorer).  The following two images are examples I would 
consider alvar shrublands. The first shows an extensive colony of Creeping Juniper 
(Juniperus horizontalis) and could perhaps be considered a dwarf shrubland.  

The second, and perhaps regular 'ole shrubland, has numerous & prominent clumps of Common Juniper (Juniperus communis) with patches of bare soil, grasses, and Shrubby-Cinquefoil (Dasiphora fruticosa).

I conclude this entry with a series of images of herbaceous dominated alvars. The first was quite moist and dominated by Spikerush (Eleocharis sp.), the second was even wetter and dominated by what I believe was Tufted Hairgrass (Deschampsia  caespitosa). The last, is a dry grassland with emergent Common Juniper and Shrubby-Cinquefoil.

Sunday, August 21, 2016

Longleaf pine restoration - bring on the fire, but first....

Elsewhere on this blog I have discussed the importance of fire for the maintenance and recovery of longleaf pine (Pinus palustris) habitats. I have not discussed the numerous challenges in being able to do so, and they can be considerable. This page will not be a full accounting of these challenges but is predicated on some of these. Namely, long-unburned stands may have extraordinary fuel loads that can be explosive and dangerous to reintroduce fire into.

Longleaf pine stand and prescribed burn near the coast of North Carolina;
flame lengths and intensity are greater than many managers would prefer 

   Longleaf "flattop"; these trees often represent remnants of
earlier forests skipped over by loggers
                                                            Bringing fire back into long-unburned stands places serious stress on the very trees fire management is intended to support. In stands where longleaf pines are sparse (image above) or where the individuals include older relicts, each tree is precious and valuable (image left). Longleaf remnants with "cat faces" (signs of previous naval stores harvest) are especially susceptible to fire damage (image below).                                                                 
Mechanically reducing the fuels in such stands can help protect high-value individual trees and lower overall fire intensity. However, doing so across large and heavily overgrown stands takes a concerted approach. Several years ago, we stepped up and took one (a concerted approach, that is).

The "concerted approach"!
Skid steer equipped with forestry cutter
We acquired a skid steer equipped with tracks to minimize ground disturbance, a special cab to protect the operator, and a "forestry cutter".  Examples of how we used it are shown below:       
  Disappearing mower and mowed swath
 through heavy "bay" fuels
Brunswick Co, NC

Mower headed straight toward remnant longleaf pine, barely evident from
a distance due to tall shrub and Pond Pine (Pinus serotina) encroachment

In these circumstances it was the perfect way to go "looking for longleaf".  

The images below show this stand before and after treatment. Note the lone Longleaf pine with the Y-shaped canopy near the center. Amazingly, a young longleaf pine was hiding in the dense brush immediately in front of this tree (click & enlarge image right). After clearing, the stand displayed the open structure typically associated with longleaf pine savannas and woodlands - a restoration success?.  Comment appreciated! 

Longleaf pine stand with relicts, after mulching treatment (same stand as above)
Note - turpentine faces on 2 of the trees.
Brunswick Co, N.C.

Tuesday, August 16, 2016

Shenandoah sinkhole ponds

Virginia Sneezeweed (Helenium virginicum) is a federally-listed "threatened" species associated with Shenandoah Valley sinkhole ponds in Virginia. A number of years ago, the species was also confirmed in Missouri in similar habitat, creating "one of the great phytogeographic mysteries of the Eastern North American flora" (1).

Virginia Sneezeweed (Helenium virginicum)

Large patch of Virginia Sneezeweed along margin of sinkhole pond, Augusta County, VA


This is a seed-banking species whose populations fluctuate widely at a given site. Flowering stems can become prolific and abundant under the right conditions (2) (image left)

Water levels in the sinks vary widely and fluctuate seasonally. The example shown below held over 12" of water while immediately adjacent ponds were completely dry.  Not surprisingly, the vegetation may also be quite variable both seasonally and between sites. For more detailed descriptions see (3) & (4) below.

Shenandoah sinkhole pond with standing water (July 12, 2016)
Note: Pin Oak (Quercus palustris) overhanging branch  

Shenandoah sinkhole pond, same site as above (August 04, 2016)
standing water still present, emergent Persicaria and Polygonum spp. superficially dominant
Shenandoah sinkhole pond with Buttonbush (Cephalanthus occidentalis) and emergent Eriocaulon

The sinkhole ponds are biologically important features of the Shenandoah Valley region and they support many other species in addition to Virginia Sneezeweed. These ponds are also extremely important for dragonflies (5) and reptiles and amphibians (4), in part, because the ephemeral water levels often restrict predatory fish populations.
Spotted Turtle (Clemmys guttata) - the only populations west
of the Blue Ridge are found in sinkhole ponds (4)
Image from coastal plain of VA
Amphibian egg masses in sinkhole pond (03-23-16)

Dragonfly exuvia on Lowland Loosestrife (Lysimachia hybrida)
in sinkhole pond, Augusta Co

Lowland Loosestrife (left) is considered significantly rare in Virginia, and known from a handful of sinkhole ponds.

A number of other rare plants may also be found:

Boltonia montana  - Augusta Co., VA (08-4-16)

Valley doll's daisy (Boltonia montana) is an extreme global rarity, known from 4 VA sites, all within a few miles of one another in Augusta County's sinkhole ponds. Described as new to science in 2006, this species also has an unusual phytogeographic pattern.

Northern St. John's Wort (Hypericum boreale)  -- Significantly rare in Virginia; known from Shendandoah sinkhole ponds and disjunct to interdunal ponds near the coast.

The ponds themselves are globally-rare and imperiled, In the two examples shown below, one has been artificially deepened and stocked with fish and the other used as a mini-landfill.

It's hard to image more important and special habitats. I hope to be able to play a small part in protecting them.

(1) Virginia Plant Atlas:
(2) Draft Recovery Plan:
(3) Descriptive Ecology:
(4) See Montane Depression Wetland types and links here (
(5) A new species of Boltonia....SIDA 22:873-886.