UVULA OF NORTH AMERICA

Bellworts

There are only five species of Uvularia, all endemic to the temperate forests of eastern North America: Uvularia floridana,  U. grandiflora, U. perfoliata, U. puberula, and U. sessilifolia (See Table 1). All five species are considered spring ephemerals and usually bloom from late March thru early May. Most wildflower enthusiasts easily recognize the genus Uvularia and its’ five species but, the genus is not free of taxonomic problems. Over the years the genus has been placed in various families within the order Liliales including: Liliaceae, Convallariaceae, Uvulariaceae, and Melanthiaceae.¹ Currently,  Weakley’s Flora of the Southeastern United States places the genus in the family Colchicaceae.²

The genus is characterized by herbaceous perennials that grow from rhizomes. The main plant body usually consists of a single or once branched stems. The plants may be 45–60 cm in height or less. Leaves alternate and, depending upon the species, may be sessile or perfoliate. The perfoliate species have entire margins while the non-perfoliate species have minutely serrated margins, often a hand-lens is needed to see the latter trait. The flowers consist of six yellow tepals that are narrowly campanulate and pendulous, hence the origin of common names such as Bellwort and Merrybells (See Figure 1). The androecium consists of six stamen that may be weakly to strongly connate at the base. The gynoecium consists of a superior tri-locular ovary and one style divided into three stigmas. Fruits are three-lobed capsules, roughly triangular to globose in shape (See Figure 2).

Figure 1: Uvularia grandiflora - Large Flowered Bellwort
Note the pendulous flower composed of six yellow tepals.

Figure 2: Fruit of Large-flowered Bellwort - U. grandiflora 
(Photo by Krzysztof Ziarnek, Kenraiz Wikimedia Commons)

TABLE 1: Comparison of Species Taxonomic Treatment 

Common Name(s)	Radford & Bell 3 (1968)	Flora of North America 4 (2003)	Weakley 2 (2015)
Florida Bellwort	U. floridana Chapman	U. floridanaChapman	U. floridana Chapman
Large-Flowered Bellwort	U. grandiflora J.E. Smith	U. grandiflora J.E. Smith	U. grandiflora J.E. Smith
Perfoliate Bellwort	U. perfoliata L.	U. perfoliata L.	U. perfoliata L.
Carolina or Appalachian Bellwort	U. pudica (Walter) Fernald	U. puberula Michaux	U. puberula Michaux
Wild-Oats	U. sessilifolia L.	U. sessilifolia L.	U. sessilifolia L.

SPECIES WITH PERFOLIATE LEAVES

The two Uvularia species with perfoliate leaves, U. grandiflora, and U. perfoliata, share the following traits: rounded stems, entire leaf margins, and obovoid-truncate capsules.

Large-flowered Bellwort, Uvularia grandiflora, and Perfoliate Bellwort, U. perfoliata, are easy to distinguish from each other. Uvularia grandiflora is the largest and most showy of the five bellwort species (See Figures 1, 3, 4, 5). Large-flowered Bellwort is commonly found in the N.C. mountain and piedmont regions where it blooms April thru May in rich mesic coves. The plant has multiple branches with 1-3 flowers per branch and each flower is preceded by a large, foliaceous, and perfoliate bract (See Figure 3, 4). The deep yellow flowers are 2.5-5 cm long, pendulous, with characteristic twisting tepals that are glabrous on the inner tepal surface (See Figures 1, 3, 4). The bright green leaves are alternating, perfoliate, and with pubescence along the veins on the abaxial side. Like the tepals the leaves are twisted and somewhat pendulous, thus giving the over-all plant a slightly wilted appearance (See Figure 3). The pendulous leaves sometimes hide the flowers making them easy to overlook.

Figure 3: Large-flowered Bellwort - Uvularia grandiflora
Note the overall wilted appearance of the plant and bright
yellow flowers composed of six twisted tepals.

Figure 4: Large-flowered Bellwort - U. grandiflora
Note the large, foliaceous, and perfoliate bract above the flower.

Figure 5: Large-flowered Bellwort - U. grandiflora
(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. 1: 519.)

Uvularia perfoliata, or Perfoliate Bellwort, may initially be confused with U. grandiflora, due to the perfoliate leaves but, a closer look will quickly settle any confusion. Perfoliate Bellwort is commonly found in the mountains and piedmont of N.C. and uncommonly in the coastal counties. It can be found in moist to dry hardwood forests and it is not unusual to find Large-flowered Bellwort and Perfoliate Bellwort growing side by side. Perfoliate Bellwort has alternate, perfoliate leaves that are glabrous and glaucous on the abaxial side. Similar to Uvularia grandiflora, the flowers are fairly large, approximately 2-3.5 cm in length, and are preceded by a large foliaceous perfoliate bract (see Figures 6, 7, 8, 10). However, unlike U. grandiflora, the tepals of U. perfoliata are very pale yellow to cream in color, not twisted, and they are distinctively papillose on the inner surface (See Figures 6, 7, 8, 9). Additionally, Perfoliate Bellwort only has one flower per branch as opposed to 1-3 for Large-flowered Bellwort. 

Figure 6: Perfoliate Bellwort - U. perfoliata
Note the lemon yellow, non-twisted tepals,
and large, foliaceous, perfoliate bract.

Figure 7: Perfoliate Bellwort - U. perfoliata
Note the large, foliaceous,  perfoliate bract preceding the flower.

Figure 8: Perfoliate Bellwort - U. perfoliata
Note the inner tepal surfaces are papillose unlike the glabrous
inner surface of Large-flowered Bellwort flowers.

Figure 9: Perfoliate Bellwort - U. perfoliataThis is a better look at the papillose tepals characteristic of Perfoliate Bellwort.
 (Photo taken by Fritz Flohr Reynolds - Wikimedia Commons)

Figure 10: Perfoliate Bellwort - U. perfoliata
(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. 1: 518.)

TABLE 2: Summary of Traits for UvulariaSpecies with Perfoliate Leaves 

(major differences are in bold-face)

Traits	Uvularia grandiflora  Large-Flowered Bellwort	Uvularia perfoliate Perfoliate Bellwort
Distribution	Common in NC mountains and piedmont	Common in NC mountains and piedmont and uncommon on Coast
Habitat	Rich mesic coves and mesic forests	Rich mesic coves, moist -dry hardwood forests
Bloom Time	April – May	April - May
Flowers	Dark yellow, twisted tepals, no glands on inner tepal surfaces,  Preceded by a large foliaceous bract,	Pale Yellow -Cream colored petals, not twisted and with distinct papillose glands on inner tepal surfaces, Preceded by a large foliaceous bract
Foliage	Bright green, pubescence along abaxial veins	Leaves glabrous and glaucous underneath
Fruits	Triangular capsule	Triangular capsule

SPECIES WITH SESSILE LEAVES

The three Uvularia species U. floridana, U. puberula, and U. sessilifolia share the following traits: sessile leaves with minutely serrated margins, angular stems, and ellipsoid capsules that are distinctly winged. See table three for a summary and comparison of the sessile-leaved species.

Uvularia floridana, or Florida Bellwort, is the only Uvularia species not found in N.C. It can be found growing in mesic to wet, low elevation, forested bottomlands and alluvial floodplains in Alabama, Georgia, Florida, Mississippi, and South Carolina. It is rare and endangered across its’ range. The plants are approximately 20-40 cm in height with alternate, sessile, dull green leaves that are fleshy with a thick cuticle. The plants are unbranched to once branched with one flower per branch. The pale white-yellowish flowers are 2-3 cm in length and are proceeded by a foliaceous bract. The tepals have long pointed (acuminate) tips. Florida Bellwort may be confused with Wild Oats, U. sessilifolia, which grows in similar habitats. Besides the fact that U. sessilifolia has darker colored tepals there are two other major characteristics that can help distinguish between Florida Bellwort and Wild Oats. First, U. sessilifolia does not have bracts subtending the flowers as U. floridana does and secondly, the tepals of U. sessilifolia are rounded to blunt tipped and not long and pointed as in U. floridana.⁵ 

Uvularia puberula or Appalachian Bellwort is common in the N.C. mountains and piedmont areas but uncommon in the coastal region. It inhabits moist to dry acidic forests.  The plants often grow in tight clumps. The alternate, sessile, leaves are dark green, lustrous (on both sides), and thick or ‘leathery” in texture. The angular stems have lines of hairs (pubescence) running along the ridges hence the specific epithet “puberula” (See Figure 11, 12). Each branch will have one to three pale yellow flowers that range from 2-2.5 cm in length (See Figure 11, 12).

This species is often hard to distinguish from U. sessilifolia. Part of this confusion may come from some natural variation of traits within U. puberula. Some botanists support two variations of U. puberula: a mountain variety, Uvularia puberula var. puberula, with broader, clasping leaves and stems, with distinct lines of pubescence, and a piedmont variety, Uvularia puberula var. nitida,  with glabrous stems and narrow leaves with cuneate bases. ^5,6 So, the latter variation, var. nitida, with its’ glabrous stems will look very similar to U. sessilifolia. It is interesting to note that Weakly and many other taxonomists do not recognize these variations.^2,6 Either way, a simple solution is to look at the underside of the leaves, remember, U. sessilifolia leaves are glaucous underneath while U. puberula are dark green and lustrous. You can also compare the stigmas, U. puberula has long stigma lobes (4-6 mm) (See Figure 13) while U. sessilifolia has very short stigma lobes (1-2 mm).

  

Figure 11: Appalachian Bellwort - U. puberula
Note the lines of fine pubescence along the ridges on the upper stem.

Figure 12: Appalachian Bellwort - U. puberula
Note there are multiple flowers per stem rather than one as in U. sessilifolia.

Figure 13: Appalachian Bellwort - U. puberula
(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. 1: 519.)

Uvularia sessilifolia is commonly called Wild Oats. It is common across the entire state of N.C. and likes moist hardwood forests and bottomlands. The plants grow in loose open colonies. The glabrous stems have alternate sessile leaves. The leaves tend to be glabrous and glaucous on the abaxial side. There is usually only one flower per branch and the pale yellow to cream colored flowers are approximately 1.3-2.5 cm in length with no bracts subtending the flowers (See Figures 14, 16). 

Figure 14: Wild Oats - U. sessilifolia
Note there is only one flower per branch,
also note the glabrous stems and leaves.

Figure 15: Wild Oats - U. sessiilifolia
(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. 1: 519.)

Figure 16: Wild Oats - U. sessilifolia
(Shenandoah National Park Public Domain Image, Uvularia sessilifolia (13083402415).jpg)

TABLE 3: Summary of Traits for UvulariaSpecies with Sessile Leaves 

(major differences are in bold-face)

Traits	Uvularia floridana Florida Bellwort	Uvularia puberula Carolina or Appalachian Bellwort	Uvularia sessilifolia Wild Oats
Distribution	Not found in N.C. Rare across its range	Common in the mountain and piedmont areas, uncommon in coastal region of N.C.	Common across entire state of N.C.
Habitat	Mesic	Mesic to dry acidic forests	Mesic forests and bottomlands
Bloom Time	March - April	March - May	March - May
Flowers	Usually 1 flower per branch, 2-3 cm long, white- yellowish, with foliaceous bract	May have 3 flowers per branch, ~ 1-2-2.5 cm long, pale yellow, no bract	Usually  1 flower per branch, ~ 1.3-2.5 cm long, pale straw yellow, no bract
Foliage	Sessile, glabrous, somewhat succulent/fleshy	Sessile, thick, rigid, dark green, and shiny on both surfaces, pubescent along abaxial veins	Sessile, glabrous, often glaucous underneath
Stems	Glabrous	Stems with pubescence along the ridges	Glabrous

The foliage of Uvularia species can also be confused with other species such as Rosy Twisted Stalk, (Streptopus lanceolatus var. lanceolatus), Solomon’s Plume, (Maianthemum racemosum var.racemosum), Solomon’s Seal species (Polygonatum biflorum, and P. pubescens), Yellow Mandarin, (Prosartes lanuginosa), and  Spotted Mandarin, (Prosartes maculta). None of the species above have perfoliate leaves which separates them all from Uvularia perfoliata, and U. grandiflora.  Solomon’s Seal and Solomon’s Plume can be distinguished from the other Uvularia species by having single, unbranched, stout stems, and by their larger size (usually > 40 cm in height). Solomon’s Plume also has petioled leaves (2-15 mm long) rather than sessile leaves to further differentiate it from Uvularia. Rosy Twisted Stalk is usually once branched similar to the sessile species of Uvularia, but the leaves are distinctly clasping and have ciliated margins. The Mandarin (Prosartes) species have multiple branching branches whereas the sessile-leaved Uvularia are unbranched or once branched. Mandarin species additionally tend to be larger (> 40 cm) than the similar sessile-leaved Bellworts. 

Hopefully, you will enjoy your new knowledge and delight in identifying our Uvularia species as you hike and explore.

RESOURCES:

1. “Uvularia.” Pacific Bulb Society | Mediterranean (Summer-Dry) Climates, www.pacificbulbsociety.org/pbswiki/index.php/Uvularia.

2. 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.

3.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.

4. Flora of North America Editorial Committee, eds.  1993+.  Flora of North America North of Mexico.  20+ vols.  New York and Oxford. Print.

5.http://www.fnai.org/FieldGuide/pdf/Uvularia_floridana.pdf

2 variations of U puberula:

https://uswildflowers.com/detail.php?SName=Uvularia%20puberula

6. Uttal, Leonard J. “Notes on Uvularia Puberula Michaux (Liliaceae).” Castanea, vol. 56, no. 1, 1991, pp. 70–70. JSTOR, JSTOR, www.jstor.org/stable/4033424.

7. All photos were taken and are the property of Tracie Jeffries unless otherwise noted.