Small-whorled Pogonia

Description:

Small-whorled pogonia is a perennial herb (Patrick et. al. 1995) with pubescent roots that grows up to 9.5 to 25 centimeters in height (USFWS 1996). A whorl of 5 or 6 leaves light green (USFWS 1996) to grayish-green are produced near the top of the stem and are usually 4 to 8 cm in length (Patrick et. al. 1995). The presence of the leaves beneath the flower(s) gives the plant its common name. The greenish-yellow flowers are solitary (or occasionally paired) and arise from the center of the leaf whorl. Flowering occurs from about mid-May to mid-June, with the flowers apparently lasting only a few days to a week or so and the species doesn't necessarily flower annually (USFWS 1996). If flower pollination does occurs, a capsule (fruit) may be formed. The capsule may contain several thousand minute seeds. No evidence of insect pollination has been observed in this species. Small-whorled pogonia is believed to be self-pollinating by mechanical processes. Its flower lacks both nectar guides and any fragrance. There is no evidence for asexual reproduction. Individual plants may not flower every year; and extended dormancy, although not scientifically documented, is purported to occur under certain conditions (USFWS 1996).

Special Identification Features:

Small-whorled pogonia may be confused with large whorled pogonia (Isotria verticillata) and Indian cucumber-root (Medeola virginiana). Large whorled pogonia has reddish-purple leaf veins, stems and flowers and the fruit stalk is longer than the capsule (fruit). In contrast, small-whorled pogonia has a pale-greenish appearance with a waxy, whitish coating on the leaves, stem, and flower and the fruit stalk is slightly shorter than the capsule (fruit). The whorled leaves of both small-whorled and large whorled pogonia, they both may resemble Indian cucumber-root. Indian cucumber root has a solid stem and white cobwebby hairs compared to the stout, hollow, smooth stems of both large and small whorled pogonias (Patrick et. al. 1995).

Habitat:

Small-whorled pogonia generally inhabits open, dry, deciduous woods with acid soil. It occurs in habitat where there is relatively high shrub coverage or high sapling density (USFWS, 1996). However, Weakley (2002) reports that the species inhabits moist forests with white pine (Pinus strobus) and Radford et. al. (1986) only reports the species inhabits wooded slopes and along streams in the Carolinas. The author observed the pictured plants above inhabiting US Forest Service lands in North Carolina growning in a mixed hardwood-coniferous forest dominated by evergreen species including white pine and hemlock (Tsuga canadensis). Patrick et. al. (1995) reports the species inhabits partially shaded gaps in mixed deciduous-conifer woods with an open understory and sparse herbaceous layer. Red maple (Acer rubrum), chestnut oak (Quercus prinus), yellow popular (Liriodendron tulipifera), and either white pine or Virginia pine (P. virginiana) are dominant canopy species. Lowbush blueberry (Vaccinium pallidum) is common in the shrub understory and Indian cucumber-root and New York fern (Thelypteris noveboracensis) are common associates in the herbaceous layer (Patrick et. al. 1995).

NatureServe (2003) reports "The high acidity of soils supporting small-whorled pogonia in New England cannot be overstated. Plants such as blue cohosh (Caulophyllum thalictroides), ginseng (Panax quinquefolius), Goldie's woodfern (Dryopteris goldiana), ramps (Allium tricoccum), etc., which indicates rich, eutrophic, mull soils never occur at these sites. Also these acidic fragipan soils are on slopes, where lateral water drainage is pronounced. Thus, highly acidic soils on level sites in New England (e.g. sand plains) which lack lateral water drainage simply do not support small-whorled pogonia. Elsewhere in its range small-whorled pogonia occurs (or occurred) on somewhat "richer", more calcareous sites - dolomitic limestone in NY, a wooded limestone hill in Missouri. At the Ontario population, the presence of blue cohosh, licorice bedstraw (Galium circaezans), lesser yellow lady's slipper (Cypripedium parviflorum) and wreath goldenrod (Solidago caesia) appears to indicate a soil more nutrient-rich than at New England populations" (NatureServe 2003).

Range:

Small-whorled pogonia is a widespread, but very local species in northeastern North America from southern Maine and Michigan, south to central and western West Virginia, western Virginia, western North Carolina, eastern Tennessee, and into northern Georgia (Weakley 2002). As of 1993, there are 104 extant small-whorled pogonia sites. Sixty-six are centered around the Appalachian Mountains of New England and coastal Massachusetts, 18 are centered around the southern Appalachians, 13 in the Coastal Plain and Piedmont of Virginia, Delaware, and New Jersey, and 7 widely scattered outlying sites, including one in Ontario, Canada. Only historic sites are known in New York, Vermont, and Maryland, and the species is believed to have been extirpated in Missouri and in the District of Columbia. Most extant sites considered viable are now protected, with site-specific protection and monitoring efforts well underway (NatureServe 2003).

Small-whorled pogonia formerly occurred in 48 counties in 16 eastern states of the United States and in Canada, but when listed as an endangered species in 1982 by the U.S. Fish and Wildlife Service, it was known to exist in only 16 counties in 10 states, and one county in Ontario, Canada. By 1991, a total of 86 sites in 15 states were extant, and by 1993, there was a extant total of 104 sites in 15 states (USFWS 1996). Small-whorled pogonia was downlisted from endangered to threatened because the number of known populations increased from 34 in 1985 to 104 in 1993. Also, the species' 1992 revised recovery plan stipulates that at least 25 percent of the plant's self-sustaining populations were protected through public ownership or private landowner management agreement. According to the October 6, 1994 Federal Register notice which officially downlisted the species, a total of 46 small-whorled pogonia sites are currently protected rangewide, 24 of which have self-sustaining populations. In the Southeast, North Carolina has two protected sites, both of which are viable; South Carolina has four protected sites, two of which are viable; and Georgia has seven protected sites, four of which are viable (USFWS 1996).