Spring Bartonia; Coastal Plain Endemic

Bartonia verna flowers (03/11/15)

Spring Bartonia (Bartonia verna) is an unexpected member of the Gentian family that appears in early spring. One of the many species first discovered by Andre Michaux, populations are restricted, or endemic, to the outer coastal plain of the southeastern US. The northernmost range consists of a single population located near VA Beach (Belden etal. 2004, reported in Castanea). Over half of the states where it has been documented consider it to be rare, including North Carolina.  A couple of the other states (MS, AL) have not explicitly considered its rarity, but like surrounding states it is almost certainly very restricted in those areas; Florida is the only state where the species is widespread (http://plants.usda.gov/core/profile?symbol=Bave2)

Spring Bartonia habitat at a site in South Carolina (03/11/15);
Pond Cypress depression pond with extensive standing water at flowering time

Sorrie & Weakley 1999 consider Bartonia's range generally synonymous with longleaf pine. The local habitat often includes wetland margins such as the example shown above on the Francis Marion National Forest.  The flowering Bartonia individuals located at this site occurred adjacent to pitcher plants, especially the Hooded Pitcher (Sarracenia minor), and Peanut-Grass (Amphicarpum muhlenbergianum). 

Bartonia verna multi-floral stem just opening

Bartonia verna in several inches of standing water; amidst brown stems of  Peanut-Grass

All Bartonia species (we have 3 in our area) are similar in having reduced leaves and root characteristics which may suggest a dependence on mychorrizal relationships to gain nutrients. Although B. verna has not been studied, Cameron & Bolin (2010) found that Bartonia virginica plants were enriched in carbon and nitrogen relative to surrounding vegetation and suggest that species is at least partially mycoheterotropic.

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Cabbage Time in Carolina!

Skunk Cabbage (Symplocarpus foetidus) is one of our earliest, native bloomers. In mid-February, I observed dozens, possibly hundreds, of individuals pushing up through leaf litter, muck, and shallow water at a site near Warrenton, NC.

The stout emerging stalks are amazingly thick and leathery to the touch. They unfurl at various rates to form leafy "spathes".  I observed incredible variation in the appearance and coloration of these, ranging from light green to heavily striped, to mottled, to almost solid dark red.




Skunk Cabbage is a member of the Araceae family, which includes mostly tropical species. In our area its closest relatives include Golden Club & Jack-in-the-Pulpit.  Symplocarpus foetidus is the only species of the genus in North America; Western Skunk Cabbage belongs to a different genus. Symplocarpus also includes some disjunct members in eastern Asia. It has been suggested the Asian and North American species of Symplocarpus have been isolated from one another for over 6,000,000 years (1).

Symplocarpus foetidus spathe; few plants observed had
developed this perfect oval shape
Warren County, NC (Feb 2015)

Skunk Cabbage open spathe revealing enclosed spadix,
Note the amount of water inside the spathe

Skunk Cabbage is famous for the ability to produce heat during early season flowering, a process sometimes called "thermogenesis". Indeed, S. foetidus is one of the most precise thermoregulators known, and is apparently able to maintain temperatures within ~ 3.5 ° C range, while ambient temperatures range over 37.5 ° C (2). Exactly what value thermogenesis conveys to the plant, if any, is unclear. Some believe it is an evolutionary hold-over present in a few primitive plant families.

According to Seymour & Blaylock (3), "there is no doubt that warming advances development and permits early flowering, but the adaptive value of this is obscure".

I observed several plants with groups of what appeared to be fruit flies buzzing around. Some authors have suggested the plant's thermogenic qualities provide a more attractive site for early season insects like these. Grimaldi & Jaenike (4) found that Skunk Cabbage is "a major breeding site" for one species of fly that "looks enough like Drosophila so that the casual observer might be confused" (5); I certainly wouldn't have known the difference! Whether these insects pollinate the flowers on the spadix is unclear.

Symplocarpus foetidus "ripe" & flowering spadix

The condition and maturity of the spadix and presence or absence of flowers was quite variable during my visit.  The following series of images shows a bit of this, as does the image above (with the dark brown spadix). However, very few spathes were open enough to easily reveal the contents. Even fewer were flowering, like the examples shown to the left. Several appeared to be just past and others much more so, while at least one spadix (below) seemed to still bedeveloping.

S. foetidus immature spadix

This ripening spadix was
lying in an open spathe,
like an Easter Egg waiting to be gathered

Bright yellow stamens exposed, zooming into these seems to show pollen that has
fallen onto the spadix surface 

North Carolina has the southernmost ranging populations of Skunk Cabbage is eastern North America. The species creeps into a few northern mountain counties in eastern Tennessee and western NC. Further east, there are 3 or 4 reported counties in the NC piedmont.  The site for these images is in Warren County, close to the Fall Line.  Although often considered a piedmont county, it sure felt like I was in the coastal plain.  The habitat was a non-alluvial wetland ranging from moist to mucky soils. Tulip Poplar & Red Maple were probably the dominant trees, but Black Gum and an occasional Pond Pine were present, Cane & White Bay Magnolia were common as well. Most of the plants were found in and around the muckiest and wettest area near the streamhead.

Skunk Cabbage habitat (Warren County); Feb 2015
most plants occurred above the standing water where a faintly developed "Y"
can be seen, just downstream a dense understory of cane develops

Skunk Cabbage habitat, same site as previous (April 2014)

References:
(1) Jun Wen, R.K. Jansen, and K. Kilgore. 1996. Evolution of the Eastern Asian and Eastern North American disjunct genus Symplocarpus (Araceae): Insights from chloroplast DNA restriction site data. Biochemical Systematics & Ecology 24: 735-747.
(2) Seymour, R. S. 2004.  Dynamics and precision of thermoregulatory responses of eastern Skunk Cabbage. Plant, Cell,& Environment. 27: 1014-1022.
(3) R. S. Seymour & A.J. Blaylock. 1999. Switching off the heater: influence of ambient temperature on thermoregulation by eastern skunk cabbage (Symplocarpus foetidus). Journal of Experimental Botany 50: 1525-1532.
(4) D. Grimaldi & J. Jaenike. 1983. The Diptera Breeding on Skunk Cabbage, Symplocarpus foetidus (Araceae). Journal of the New York Entomological Society 91: 83-89.
(5) H. D. Stalker, 1945; On the Biology and Genetics of Scaptomyza graminum Fallen (Diptera: Drosophilidae).

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Purple Mountain Pitcher Plants - New & Improved!

Purple Mountain Pitchers grow well in naturally occurring beds of Sphagnum moss
like these growing wild in Transylvania County, NC

Ron Deterrmann, has been tireless in his efforts
to secure conservation for Purple Mountain Pitchers  

                                                               Purple Mountain Pitcher Plants occur naturally only in a small region of the southern Appalachians (western NC, adjacent SC and GA).  There has been relatively little conservation attention focused on this narrow endemic, in part due to the relatively recent recognition of its distinctiveness. Schnell & Determann (Castanea 1997) published the new varietal status, thereby bringing needed attention to these unique plants.  


The NC Plant Conservation Program "protects" portions of two of the 8 known populations in the state (although perhaps more populations will become known as the NC Natural Heritage Program is just beginning to keep documentation on this plant for the first time (2014).

One of two protected populations mentioned above has approximately 150 clumps of pitchers and comprises what is thought to be the largest known population in the state. It is unclear why this population is so large compared to others in the region.  We do know that Sarracenia purpurea spreads slowly; Ellison & Parker (American Journal of Botany 2002) documented only a 5 cm median dispersal distance for pitchers in the northeastern US.  Further, Gotelli and Ellison (Ecology 2002) found that Purple Pitchers don't reproduce until individual rosettes reach 10 cm in diameter.  Our Southern Apps variety grows vigorously and flowers profusely in sunny & open habitats, as shown in the following image. In contrast, pitchers subjected to heavy

Mass flowering in an open, sunny, yet constantly moist habitat

shade lose vigor, diminish in size, and cease flowering.  The example shown below displays etiolated leaves typical of shading. This clump is actually smaller than the surrounding Galax foliage and has little chance of flowering or trapping insects. The site where it occurs has been heavily shaded for 20 + years.  It is unclear how long an individual pitcher clump or rosette can survive in dense shade.  Gotelli & Ellison (Ecology 2002) suggest rosettes may persist for 30-50 years, but this longevity is likely to be strongly affected by shading.  In any case, the diminished vigor translates to loss of reproduction, perhaps a significant reason other known populations are much smaller.  

Our large population was almost certainly larger at one time. We have documentation that the pitchers were "once so plentiful they sold for 50 cents a piece".  Even today, pitchers continue to be taken or poached hindering population expansion.  The first image below shows where an entire rosette was taken (depressed area directly in front of the remaining clump). The second image shows a clump partially removed (note the bud forming).  I guess in both cases the losses could have been far worse, eco-conscious poachers?

In spite of the poachers, we have extensively re-opened the site by removing dense shrubs.  Precise demographic data are lacking but we counted 32 flowers in 2012, 94 flowers in 2013, and 114 flowers in 2014. The majority of these flowers seem to be producing seed heads. It has been estimated that Northern Pitchers produce approximately 1000 seeds per head (Gotelli and Ellison, Ecology 2002). Although germination rates may be low, if seed production continues the population could begin to rebound. In fact, on a recent visit Ron Determann pointed out a few true seedlings..... with luck, continued management, patience, and support of our local poaching community the population may continue to rebound!

Purple Mountain Pitcher seed capsule 

Seedling Purple Pitchers

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Blue Ridge Huckleberry (Gaylussacia orocola)

Gaylussacia orocola is narrowly endemic to North Carolina, found in only a couple western counties. Like many other rare plants of the region, it inhabits "mountain bogs" one of the rarest habitat types we have. It is a small deciduous shrub that can grow in association with other heaths like Crackleberry (Gaylussacia baccata) and Highbush Blueberry (Vaccinium fuscatum). At the site of these images it grows under a fairly dense shrub layer containing the previously listed species, as well as Mountain Laurel (Kalmia latifolia), Winterberry (Ilex verticellata), American Holly (Ilex opaca), and a scattering of other woody plants.

Blue Ridge Huckleberry (Gaylussacia orocola) flowering in early June (Transylvania County, NC); adjacent Crackleberries were already in fruit

Blue Ridge Huckleberry (Gaylussacia orocola) flowers and young leaves; note the "stipitate-glandular" hairs


Blue Ridge Huckleberry leaves with "mucronate" tips

Many of the uppermost (sun-exposed) leaves were red-tinged

The conservation status of Blue Ridge Huckleberry is unclear.  Ed Schwartzman told me he thought there are around 10 recorded populations in North Carolina but only 1 may be extant. It's more than a little surprising given the rarity and documented loss of mountain bogs, the extremely limited natural range, and the few known populations that this species is not considered "imperiled" in North Carolina.

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