Sunday, March 29, 2015

American Bladdernut (Staphylea trifolia)

American Bladdernut is widely distributed across the eastern United States from approximately western New England across much of the midwest into eastern Minnesota. In the extreme southern US, it is less frequently encountered but is scattered across MS, AL, and into the Piedmont of the Carolinas.   The presence of dangling "bladders" make the small tree easy to recognize throughout the winter.

The so-called bladders are actually papery textured, three-chambered capsules enclosing one or more hard, stony seeds. I opened a handful of capsules, expecting one seed in each of the 3 chambers. However, most had only one seed per capsule, a couple had 2, and only a single pod had 3 seeds. With a much larger sample, Harris (1912), writing in Botanical Gazette, found that longer pods tended to produce more ovules or seeds.

Seeds are bright & shiny, and bead-like. Those of the European species, S. pinnata, were regularly and widely used in rosaries (Lukzaj 2009, Dendrologicznego). Celts planted them on graves and other significant sites, and fossil remains are often associated with Roman & Medieval archaeological sites, often outside of its perceived native range (see Latalowa 1994 in Vegetation History & Archaeobotany).

In North Carolina our species, Staphylea trifolia, is typically a "bottomland" or "riparian" species; the bladders are thought to aid seed dispersal . I dropped a handful in water and the image (left) confirms, they do indeed float!  Perhaps not surprising, most naked seeds sunk rapidly. 

Water dispersal may explain why most of the stems I have observed along the Eno River in Piedmont of NC, are close to, or even overhanging the river.  

Typical habit of American Bladdernut
Along Eno River, Durham Co, NC
Note multiple, whitish-gray trunks above River Oats (Chasmanthium latifolium)

Image below (near the "Pump Station" on Eno River)
This part of the river floods more regularly than the above site, consequently
shows more extensive damage presumably from flood debris (see ground nearby)

American Bladdernut has oppositely arranged twigs and buds. Reddish-brown buds are evident in the winter (below; Jan 25, 2015). 


In the North Carolina Piedmont, Bladdernut buds began bursting open on March 22, 2015 (see above). Soon, the trifoliate leaves will be fully developed as shown on the specimen below:

Saturday, March 21, 2015

Sessile Trillium - a rare myrmecochore in North Carolina

Trillium sessile: red petalled form in northeastern NC
Sessile Trillium occurs on the southern periphery of its natural range in northeastern North Carolina near the Roanoke River.  In Carolina this Trillium is known from two counties and is considered "Threatened" in the state.  Most individuals seem to have red petals as shown on the image above, but some individuals (as shown below) have greenish-yellow petals, apparently due to diminished or absent anthocyanins (for more information see Les etal. 1989; American Journal of Botany). 

Trillium sessile: light color form
Image date: 04/09/14

Sessile Trillium is widespread and common in the Missouri Ozarks and parts of the midwestern US. It is much less widespread east of the Appalachians although it does range across much of the Virginia Piedmont and into the coastal plain.  How does a species considered a "myrmecochore" (adapted for ant dispersal) develop a range like this?

For an excellent chance to see this rare plant in North Carolina, consider joining the Friends of Plant Conservation on April 07, 2015.  

More information can be found here:

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 (

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.