Buttercup family (Ranunculaceae)
Description: This native perennial plant is about ½2' tall. It consists of a loose cluster of basal leaves on long petioles and a flowering stalk with a few alternate leaves. The basal leaves are up to 4" long and across; they are palmately cleft into about 5 deep lobes, which are in turn divided into 2-3 shallow secondary lobes. These leaves are usually sparsely pubescent and they may have a few dentate teeth along the margins. Their petioles are pubescent or hairy and rather stout. The alternate leaves are clustered near the base of the flowering stalk and they are few in number; their appearance is similar to the basal leaves. The flowering stalk is erect, stout, and rather fleshy; it is whitish green or whitish red and usually covered with fine white hairs. Less often, this stalk is glabrous. A raceme of flowers up to 6-8" long occurs along the upper half of this stalk; each raceme may consist of 6-24 flowers. Each flower is about ¾1" across, consisting of 5 petal-like sepals, 4 petals, and 3 inner pistils. The sepals spread outward from the center of the flower and they are usually some shade of purple or blue-violet; far less often, they are white. The upper sepal forms a long nectar spur behind the rest of the flower; this spur angles upward and is fairly straight. A few cobwebby hairs may occur along the nectar spur and the posterior surface of the sepals. The upper two petals are quite small and usually white toward the base; they extend backward in the nectar spur. The lower two petals are quite hairy and usually purple or blue-violet like the sepals. These small petals surround the whitish opening that leads to the nectar spur. The pedicels are about as long as the flowers and usually pubescent. The blooming period occurs during the late spring and lasts about 3 weeks. Each fertilized flower is replaced by three spreading follicles (a seed capsule that splits open along one side). Each follicle is oblongoid and angular, terminating in a short beak; it contains several chunky seeds. The root system is tuberous and can form vegetative offsets.
Cultivation: The preference is light dappled shade or partial sun, mesic to slightly dry conditions, and a soil that is rocky or loamy. Vegetative growth and flowering proceed quickly during the spring.
Range & Habitat: Dwarf Larkspur occurs occasionally in the southern half of Illinois, while in the upper half of the state it is uncommon or absent. Habitats include deciduous mesic woodlands, moist ravines and thinly wooded slopes (often rocky), thinly wooded bluffs, and partially shaded cliffs along river banks. This species displays a preference for hilly woodlands.
Faunal Associations: The flowers are pollinated by long-tongued bees primarily, including bumblebees, Anthophorid bees, and some Miner bees. These insects suck nectar and collect pollen. The flowers are also visited by butterflies, skippers, and Sphinx moths, but Charles Robertson of Flowers and Insects (1929) didn't think they were effective at pollination. He also observed the Ruby-Throated Hummingbird visiting the flowers. The caterpillars of the moth Heliothis phloxiphagus (Spotted Straw) eat the flowers of Delphinium spp., while the maggots of Phytomyza delphinivora (Delphinium Leaf-Miner Fly) tunnel through the leaves. The foliage of Dwarf Larkspur is toxic to most mammalian herbivores.
Photographic Location: A wildflower garden at Crystal Lake Park in Urbana, Illinois.
Comments: The attractive flowers have the shape of the little starmen in children's cartoons. Dwarf Larkspur is shorter and blooms earlier than other Delphinium spp. this is an adaptation to its woodland habitat. It is distinctive in having 3 widely spreading follicles per flower, while other Delphinium spp. have follicles that are more or less united at the base. There is some variation in color of the flowers, appearance of the leaves, and hairiness of the stalks and leaves across different populations of Dwarf Larkspur. The only other species in this genus that is native to Illinois is Delphinium carolinianum (Tall Larkspur), which consists of an eastern subspecies with blue-violet flowers and a western subspecies with pale blue or white flowers (the latter is often called Prairie Larkspur). Various Larkspurs are often cultivated in flower gardens, but they are usually native to the Pacific Northwest, or annual species from the Mediterranean area of Europe.