Larkspur is a handsome tall forb in the buttercup family (Ranunculaceae) with spurred deep-purple flowers that grows in lush areas in forests, thickets, meadows and streambanks from the lowlands into the alpine zone. Plants grow 50-130 cm tall from a woody caudex. All the leaves grow along the stem, alternately arranged near the base of the plant. Leaves are palmately divided, the segments further cleft into pointed segments. Leaves are dark green above and lighter below, with visible veins on the upper surface. The thick, hollow stem is green or reddish-purple, and supports a many-flowered raceme at the top. Plants are sparsely hairy. Each flower is on a 1-3 cm long pedicel. Flowers are bilaterally symmetric with a prominent spur extending towards the back. Sepals (the more prominent part of the flower) are 17-24 mm long, rounded at tips, blue to dark purple. Flowers mature into 2-3 follicles, elongate capsules attached in the middle to each other with a pointed tip. These purple-veined dry fruits split along one seam, releasing winged seeds. Another plant in Denali with bilaterally symmetric blue flowers and much-dissected leaves is Aconitum delphiniifolium, but that species has a few rounded, helmet-like flowers, not a spike-like raceme of spurred flowers.
Delphinium glaucum is a perennial species, plants living more than eight years (Looman 1984). Flowers are protandrous, meaning the stamens release pollen before the stigmas are receptive (Ishii and Harder 2006). Mountain larkspur flowers in mid-summer.
This species is monoecious with bisexual flowers. Mountain larkspur is pollinated by bees (Looman 1984). Flowers mature into 2-3 follicles, which split along one seam, releasing winged seeds. Seeds are dispersed by wind and gravity. The seeds remain viable in the soil for at least two years, and require moist stratification and warm temperatures in order to germinate (Looman 1984).
The whole plant contains a toxic alkaloid. The Dena'ina used an infusion of the root to wash away lice, or drank it to treat tuberculosis (Kari 1995).
Mountain larkspur is endemic to western North America. This species grows in sites from Alaska to the Northwest Territories, southward through the Rockies to Utah and Colorado, with scattered occurrences in the mountains of the Pacific Northwest, California and Arizona. In Alaska, D. glaucum occurs from the Brooks Range to Southcentral Alaska, and is common and widespread in central interior Alaska, with localities in northern Southeast. In Denali, D. glaucum occurs mainly in and near the mountains, occurring on both sides of the Alaska Range crest, with occasional occurrences in the lowlands.
This species is by far the more abundant of the two Delphinium species in the study area. Primarily alpine and subalpine, this species is found from 91 to 1252 m, the average site at 910 m. more frequent on southern aspects. Common on steep slopes.