Wildflowers of the United States

Carolina Larkspur, Blue Larkspur, Glade Larkspur, Prairie Larkspur, Pine Woods Larkspur - Delphinium carolinianum

• ssp. carolinianum (Blue Larkspur, Prairie Larkspur) will usually not have its basal leaves present at anthesis (while flowering) - all other subspecies' basal leaves are normally present at anthesis. The sepals of this subspecies are usually blue or purple, but occasionally white. This species has a wide distribution in the south extending up into the midwest as far north as Iowa.
• ssp. calciphilum (Glade Larkspur) is found east of the Mississippi in limestone glades of AL, GA, KY, and TN. Sepals are white to pale blue. This is generally the shortest of the subspecies, usually no more than 18 inches tall. This is the subspecies presented on this page.
• ssp. vimineum (Pine Woods Larkspur, Blue Larkspur) is another widely distributed subspecies, found in the midwest from Texas north to Minnesota and the Dakotas into Manitoba, Canada. It will rarely have more than 3 leaf divisions, and the flowers may have blue or white sepals.
• ssp. virescens - (Plains Larkspur, White Larkspur) Some authorities consider this subspecies to be synonymous with ssp. calciphilum. With some minor morphological differences in the leaves and height (ssp. virescens more in both attributes), ssp. virescens is found west of the Mississippi River in deeper soils, while ssp. calciphilum is found east of that river in shallow soils of limestone glades. The sepals are white or very pale blue.

Site: Couchville Cedar Glade, Davidson County, TN Date: 2017-May-11	Photographer: Gerald C. Williamson Nikon D7000 Tamron SP 90MM f/2.8 AF Macro
The flower of Delphinium carolinianum can be from white to pale blue to deep blue or purple, depending on the subspecies. Most of the color is from the 5 petal-like sepals which spread around the rest of the flower. It has 4 petals, the upper two enclosed in (or exserted from) the upper sepal, which is spurred, with the spur containing the nectary. The lateral 2 sepals flank the lower 2 petals which have two lobes each. The stamens are held below the lower 2 petals, but can seem to be held up by the lower 2 sepals.
Site: Couchville Cedar Glade, Davidson County, TN Date: 2017-May-11	Photographer: Gerald C Williamson Nikon D7000
The stamens are held below the lower 2 petals, but can seem to be held up by the lower 2 sepals. While the sepals are glabrous to slightly hairy, the petals are definitely hairy. The hairs can be white, yellow, or blue. The pedicel can be glabrous to glandular hairy.
Click on the photo for a larger image
Site: Couchville Cedar Glade, Davidson County, TN Date: 2017-May-11	Photographer: Gerald C Williamson Nikon D7000
The inflorescence of Carolina Larkspur is a raceme of up to 30 or 40 white to blue or purple spurred flowers. The plant can grow up to 4 feet tall, with ssp. carolinianum generally the tallest of the subspecies.
Click on the photo for a larger image
Site: Couchville Cedar Glade, Davidson County, TN Date: 2017-May-11	Photographer: Gerald C Williamson Nikon D7000
Both the cauline (stem) and basal leaves are on petioles, and are divided into relatively narrow segments. The number of leaf segments, and whether or not they are further subdivided is a diagnostic for subspecies.On the leftmost basal leaf in this plant you can see the 3 distinct leaf segments, each of which are further lobed.
Click on the photo for a larger image
Site: Couchville Cedar Glade, Davidson County, TN Date: 2017-May-11	Photographer: Gerald C Williamson Nikon D7000
The petioles get shorter up the plant. The stem is usually pubescent to densely hairy, frequently glandular.
Click on the photo for a larger image

• Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
• Weakley's Flora of the Southern and Mid-Atlantic States (2015)
• Wildflowers of Tennessee, the Ohio Valley and the Southern Appalachians: 2nd Edition
• USDA Plants Database
• Integrated Taxonomic Information System