NORTH CAROLINA PHACELIA SPECIES

Figure 1: Phacelia bipinnatifida (Fernleaf Phacelia)

There are approximately 200¹ species of Phacelia native to North and South America. They are annual or perennial herbs, usually hairy and or glandular. Plants usually have basal leaves and alternate cauline leaves that, depending on the species, range from simple to bipinnately compound. The inflorescence is usually a one-sided cyme that starts off tightly coiled hence, one of the common names “scorpion-weed”. The flowers are actinomorphic and pentamerous consisting of five separate or fused sepals, five petals fused at the base, and five stamen fused to the petals (Figure 1). The ovary is superior and usually composed of two fused carpels which will later mature into a capsule with numerous seeds. The genus is traditionally placed within the family Hydrophyllaceae but there has been a recent trend to move it into the Boraginaceae.²  According to Weakley’s, Flora of the Southern and Mid-Atlantic States, ³ there are eight native Phacelia species in the southeastern U.S., with six of those species found within North Carolina.

TABLE 1: Comparison of N.C. Species Taxonomic Treatment

Common Name(s)	Radford & Bell 4 (1968)	Weakley 3 (2015)
Fern-leaf or Purple Phacelia	P. bipinnatifida Michaux	P. bipinnatifida Michaux
Eastern Buttercup Phacelia		P. covillei S. Watson ex A. Gray
Appalachian Phacelia	P. dubia (L.) Trelease	P dubia (L.) Trelease var. dubia
Fringed Phacelia	P. fimbriata Michaux	P. fimbriata Michaux
Flatrock Phacelia	P. maculata Wood	P. maculata Wood
Miami-Mist	P. purshii Buckley	P. purshii Buckley
Western Buttercup Phacelia	P. rannunculacea (Nuttall) Constance

FRINGED PHACELIA SPECIES

There are two species in N.C. with fimbriated petals; Phacelia fimbriata, and P. purshii. Phacelia fimbriata is commonly called Fringed Phacelia or Blue Ridge Phacelia. As the common name “Blue Ridge Phacelia “ implies, this species is a Southern Appalachian  endemic. It is considered  overall uncommon but, in some areas it forms impressive displays of flowers across the forest floor. Fringed Phacelia prefers rich moist woodland slopes and alluvial woods. The 1.3 cm (.5 inches) wide flowers are white or rarely a pale lilac with deeply fimbriated lobes. (Figures 2, 3, 5). The lower leaves are  often pinnately compound and petioled while the upper leaves are pinnately lobed and sessile (Figure 4, 5 ). Depending on the elevation and other factors look for blooms during May through June. The photos below (Figures 2, 3, 5) were taken early May along the Blue Ridge Parkway near Grandfather Mountain at an elevation of 1219 meters (4000 ft.).

Figure 2: Phacelia fimbriata (Fringed Phacelia or Blue Ridge Phacelia)
- notice the deeply fringed petals.

Figure 3: Phacelia fimbriata (Fringed Phacelia) showing the typical white corolla color as opposed to light blue-purple seen in the similar P. purshii.

Figure 4: Fringed Phacelia - notice the 
sessile, alternate cauline leaf with pinnate lobing.

Figure 5: Phacelia fimbriata - USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 3: 71.

Phacelia purshii or Miami Mist is our second species with fimbriated petals (Figures 6, 7, 8, 9). Unfortunately, it is very similar morphologically to Fringed Phacelia and the two species are often confused with each other. Table two highlights some of the differences between Fringed Phacelia and Miami Mist. Initially, it seems like it would be easy to distinguish between the two species but, a closer look shows many areas of overlap such as habitat, elevation, corolla color, plant size, and leaves. Luckily, a good 10x hand lens may help solve the dilemma, look for appressed hairs on the stems of P. purshii and spreading hairs on P. fimbriata (Figure 10). Miami Mist usually blooms between May and June.  The photos below were taken late April in the Porter Creek area in the Great Smoky Mountain National Park (Figures 6, 7, 8). The elevation at this site was around 710 meters (2300 ft).

 TABLE 2: A Comparison and Contrast of Traits Between Phacelia fimbriata and P. purshii ^{3, 4, 6, 7}

TRAIT	FRINGED PHACELIA P. fimbriata	MIAMI MIST P. purshii
Distribution	Narrow distribution, a Southern Appalachian endemic found in Virginia, North Carolina, Tennessee, Alabama, and Georgia	Widely distributed from Canada and most of the Eastern U.S.
Elevation	Grows mostly at higher elevations, usually elevations > 1,200 m (4000 feet)	Grows mostly at lower elevations,  usually < 1,070 m (3500 feet)
Habitat	Somewhat restricted - rich moist wooded slopes and alluvial plains	Found in a wider variety of habitats - rich moist wooded slopes and alluvial plains, and disturbed areas such as fields, roadsides and meadows
Corolla Color	Corolla mostly white, rarely tinged with light blue or lilac, also fringes are deeply lobed	Corolla mostly a pale to medium lavender color, but may be white or dark lavender, fringes are not as deeply lobed
Number of  flowers per inflorescence	~ 5-15	~ 10-25
Pubescence	Plant overall sparsely pubescent – glabrous, hairs on stems are spreading	Plant overall very pubescent and hairs are appressed (point upward)
Growth Habit	Plants overall smaller in size and more procumbent	Plants overall larger in size and more erect

Figure 6: Phacelia purshii - Miami Mist- notice the blue-lavender corolla 
color and fimbriated petals that are not as deeply lobed as P. fimbriata.

Figure  7 : Phacelia purshii - Miami Mist

Figure 8: Phacelia purshii - Miami Mist - notice the 
alternate pinnately lobed leaves and helicoid cymes.

Figure 9: Phacelia purshii - USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 3: 70.

Figure 10: Comparison of stems hairs on Phacelia fimbriata vs. P. purshii.

NON-FRINGED PHACELIA SPECIES

North Carolina’s other four phacelia species are non-fringed. Probably the best known of these four is Phacelia bipinnatifida or Fernleaf Phacelia. It is very common in the mountains and uncommon to rare in the upper piedmont. The plants like to grow in rich rocky cove forests. The inflorescence is a helicoid cyme typical of the genus. The flowers are about 1.27 cm (.5 in.) across and the corolla color may be white to bluish-purple to purple with white centers (Figures 1, 11, 12). The most common color I see is purple and occasionally in large populations you will find a few plants with all white flowers. The stamen are noticeably hairy and extend beyond the petals (Figure 13 ). Plants have both basal and alternate cauline leaves that are pinnately lobed (3-5 lobes) and coarsely toothed. Leaves may or may not be mottled (Figures 14, 15 ). This latter trait is one reason P. bipinnatifida (Figure 16) is often confused with a close relative Hydrophyllum virginianum, Virginia or Appalachian Waterleaf (Figures 15, 17, 18). Table 3 shows some of the similarities and key differences between the two species.

TABLE 3: A Comparison and Contrast of Traits Between Phacelia bipinnatifida and Hydrophyllum virginianum

TRAITS	Fernleaf Phacelia Phacelia bipinnatifida	Appalachian Waterleaf Hydrophyllum virginianum
Distribution in N.C.	Common in N.C. mountains and rare in the piedmont	Uncommon in N.C. mountains and rare in piedmont
Habitat	Rich, moist, often rocky woods and streambanks	Rich, moist wooded slopes and alluvial woods
Flowers	The five petals can range in color from white - pale lavender - deep blue-purple Hairy filaments Style divided to middle	The five petals range in color from  white - pink - light lavender Hairy filaments Style only divided at tip
Leaves	Leaves alternate, simple, basal and cauline, pinnately lobed (3-5 lobes), margins coarsely toothed, and leaves often mottled, leaves pubescent	Leaves alternate, simple,  basal and cauline, pinnately lobed (5-7 lobes), margins coarsely toothed, and leaves often mottled, glabrous to sparsely pubescent
Bloom Time	April - May	May- June

Figure 11: Phacelia bipinnatifida (Fernleaf Phacelia) - note the non-fimbriated purple flowers with white centers, and hairy filaments that extend past the petals. Figure 12: A large population of Fernleaf Phacelia in bloom.  Figure 13: A close-up of a Fernleaf Phacelia flower showing the hairy filaments extending well past the petals. Figure 14: Basal leaves of  Phacelia bipinnatifida showing the mottled pattern and pubescence. Figure 15:  Basal leaf of Hydrophyllum virginianum By Salicyna - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=58225291

Figure 16: Phacelia bipinnatifida - USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's 

Sons, New York. Vol. 3: 69.

Figure 17: Hydrophyllum virginianum - notice the style is only divided at the tip.

Figure 18: One way to tell Phacelia species from Hydrophyllum is by the styles. In phacelia species the styles are divided approximately half the length of the style while in Hydrophyllum the styles are only divided at their tips.

Phacelia maculata or Flatrock Phacelia superficially looks very similar to P. pinnatifida but,  several key features quickly distinguish Flatrock Phacelia from Fernleaf Phacelia. One major feature, implied by the common name “Flatrock Phacelia”, is the habitat of P. maculata. Flackrock Phacelia is a granitic community endemic. It is only found in a few areas within the piedmont regions of four states (N.C., South Carolina, Georgia, and Alabama) and is considered rare to endangered across its range.⁸ For N.C. it is only recorded in Cleveland County and may be extirpated. Other differences between Fernleaf and Flatrock Phacelia is that the latter has very prominent cilated margins on the sepals, the throat of the flower is not white (as in Fernleaf Phacelia), and ten dark spots at the base of the petals (Figure 19).

Figure 19: Phacelia maculata (Flatrock Phacelia) - note the
purple spots at the base of the petals. Photo by Will Stuart

A third non-fimbriated species is Phacelia covillei or  Eastern Buttercup Phacelia (Figures 20, 21, 23). In N.C. it is endangered and only found in nine piedmont counties along the drainage basins of the Tar, Cape Fear, and Roanoke Rivers. It grows along the floodplains and adjacent river slopes. Notice from Table one that Radford and Bell did not have this species occurring in N.C. This is because it was once considered to be the same as Phacelia rannunculaceae. and some botanists still do not recognize P. covillei as a separate species.⁹ Weakely³ warns that Eastern Buttercup Phacelia can be confused with P.  rannunculaceae, Western Buttercup Phacelia, and Nemophila aphylla (Figures 22, 24, 25),  Smallflower Baby Blue Eyes. The former species does not occur in N.C., so I will only focus on  distinguishing Eastern Buttercup Phacelia from Smallflower Baby Blue Eyes. Table 4 shows the similarities and differences between P. covillei and N. aphylla.  A good place to look for  Eastern Buttercup Phacelia is Raven Rock State Park early in the spring (March-April).

TABLE 4: A Comparison and Contrast of Traits Between Phacelia covillei and Nemophila aphylla

TRAITS	Phacelia covillei Eastern Buttercup Phacelia	Nemophila aphylla Smallflower Baby Blue Eyes
Distribution in N.C.	Rare in piedmont	Uncommon in Piedmont and coastal plain
Habitat	Wooded floodplains and slopes	Rich moist woods, wet disturbed areas, wooded floodplains and alluvial forests
Flowers	Corolla is pale blue to lavender Corolla tubular to campanulate Flowers are very small < 1 cm Multiple flowers (2-6) in terminal cymes	Corolla is white to light blue Campanulate Flowers are very small < 1 cm Flowers are solitary on pedicels opposite the leaves Sepals have small reflexed bracts
Leaves	Leaves alternate and pinnately lobed	Leaves alternate and pinnately lobed
Bloom Time	April	March - May

Figure 20: Phacelia covillei or  Eastern Buttercup Phacelia -
note the campanulate corolla. Photo by Keith Board (http://getyourbotanyon.blogspot.com/2009/05/phacelia-covillei-phacelia-ranunculacea.html)

Figure 21 : Phacelia covillei or  Eastern Buttercup Phacelia -
Photo by Keith Board (http://getyourbotanyon.blogspot.com/2009/05/phacelia-covillei-phacelia-ranunculacea.html)

Figure 22: Phacelia covellei (Eastern Buttercup Phacelia) and Nemophila aphylla (Smallflower Baby Blue Eyes), are often difficult to tell apart from each other. But one key difference its found on the sepals. Nemophila has unique reflexed bracts associated with its sepals. Bracts are lacking on the sepals of  Phacelia covellei.

Figure 23: Phacelia covillei - Nathaniel Lord Britton, Addison Brown - An Illustrated Flora of the Northern United States, Canada and the British Possessions: From Newfoundland to the Parallel of the Southern Boundary of Virginia, and from the Atlantic Ocean Westward to the 102d Meridian, Volume 3.

Figure 24: Nemophila aphylla (Smallflower Baby Blue Eyes)
 - Photo taken by Patrick Alexander March 21, 2008

Figure 25: Nemophila aphylla - USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 3: 67.

        The last Phacelia species in N.C. is Phacelia dubia var. dubia, commonly called Appalachian Phacelia, or Small Flower Scorpion Weed (Figures 26, 27, 28). It is common in the mountains and piedmont and rare along the coastal plain. Appalachian Phacelia can grow is a wide range of habitats including forests, wooded floodplains, granitic outcrops, and disturbed areas such as fields and roadsides.  The 8-11mm (.31 - .43 in) flowers are white to pale blue with yellowish-green centers. This species is easy to identify. The unfringed petals separate it from P. fimbriata and P. purshii. The larger bowl-shaped flowers set it apart from P. covelii, and the light blue corolla with yellowish-green center distinguishes it from P. bipinnatifida and P. maculata. The photos below were taken in late April along the Blue Ridge Parkway north of Asheville (Figures 26, 27).

Figure 26: Phacelia dubia var. dubia, or Appalachian Phacelia -
note the pale blue flowers with yellowish-green centers.

Figure 27: Figure 24: Phacelia dubia var. dubia, or Appalachian Phacelia

Figure 28: Phacelia dubia - USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 3: 69.

             I hope my readers have enjoyed this article. and that it has inspired them to go out and explore our amazing native plants!

“Wildness is the preservation of the World.” 

 Henry David Thoreau

RESOURCES:

1. “The Plant List - A Working List for All Plant Species.” Home - The Plant List, Royal Botanic Gardens, Kew and Missouri Botanical Garden, Sept. 2013, www.theplantlist.org/1.1/about/.

2. “Jepson Herbarium: Jepson Flora Project: Jepson EFlora: Phacelia Distans.” Guide Page for Fucus Gardneri Silva, ucjeps.berkeley.edu/eflora/eflora_display.php?tid=37450.

3. Weakley, Alan S. Flora of the Southern and Mid-Atlantic States. Chapel Hill, NC: U of North Carolina Herbarium, North Carolina Botanical Garden, U of North Carolina, Chapel Hill, 2015. Print.

4. Radford, Albert Ernest, Harry E. Ahles, and Clyde Ritchie Bell. Manual of the Vascular Flora of the Carolinas. Chapel Hill, NC: U of North Carolina Press, 1983. Print.

5. United States, Congress, Department of Natural and Cultural Resources, et al. “Natural Heritage Program List of Rare Plant Species of North Carolina 2016.” Natural Heritage Program List of Rare Plant Species of North Carolina 2016.

6. Glass, Pamela Michele, "Evidence of Ecological Speciation in Phacelia." (2007). Electronic Theses and Dissertations. Paper 2143. h p://dc.etsu.edu/etd/2143

7. Chester, W. & Wofford, Eugene & Shaw, Joey & Estes, Dwayne & Webb, H.. Guide to the Vascular Plants of Tennessee. Knoxville: The University of Tennessee Press, 2015. Project MUSE.

8. Jerry M. Baskin and Carol C. Baskin, GERMINATION ECOLOGY OF PHACELIA DUBIA VAR. DUBIA IN TENNESSEE GLADES, American Journal of Botany, 58, 1, (98-104), (1971).

9. Sewell, M., and M. A. Vincent. 2006. Biosystematics of the Phacelia ranunculacea complex (Hydrophyllaceae). Castanea 71: 192–209.