This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Delphinium exaltatum Ait. Hort. Kew. 2: 244. 1789.
Slender, 2°-6° high, glabrous or sparingly hairy below, densely pubescent above. Leaves large, all but the upper petioled, deeply 3-5-cleft, the divisions lanceolate or oblanceolate, cuneate, acuminate, cleft and toothed toward the apex, upper ones reduced to small linear or lanceolate bracts subtending the flowers; racemes dense, elongated (sometimes over 1° in length); flowers purple or blue, 8"-10" long, downy-pubescent, the lower pedicels about I" long; spur nearly straight, 4" long; follicles 3, erect, 4"-5" long, pubescent, tipped with a subulate beak.
Delphinium Treleasei Bush; Davis, Minn. Bot. Stud. 2: 444. 1900.
Perennial, with fascicled roots, glabrous, slightly glaucous, 2°-4° high, the stem-leaves few. Basal leaves long-petioled, deeply pal-matifid into linear segments 2" wide or less; raceme loose, pyramidal in outline, often a foot long, the pedicels very slender, ascending, the lower 2'-4' long, sometimes branched, the upper shorter: flowers blue or blue-purple; sepals and spur about equal in length, puberulent; spur straight, 3/4' long; sepals narrowly ovate; bractlets borne somewhat below the calyx; petals yellow-bearded; follicles 3, erect, slightly puberulent.
Finely puberulent, at least above; stem slender, simple, 8'-1 1/2° high from a cluster of tuberous roots near the surface of the ground. Leaves firm, the lower pedately divided into linear lobes or segments, long-petioled, the petioles sheathing the stem, the upper short-petioled, less divided; flowers in the upper axils and forming a loose terminal raceme, blue, slightly villous, slender-pedicelled; lower pedicels 1'-2' long, longer than the flowers; sepals oblong, shorter than the slender spur; lower petal 2-cleft, with a tuft of hairs about the middle; follicles 3, appressed-pubescent; seeds wing-angled above.
Western Nebraska and Colorado to Wyoming, and British Columbia. May-June.
Stem slender, more or less pubescent, 1°-2° high. Leaves deeply cleft into linear toothed or cleft segments; raceme terminal, 4'-8' long; flowers pedicelled, blue, about 1' long, the spur curved upward, horizontal or nearly erect, 8" long; follicles 3, erect or slightly spreading, downy, 7"-9" long, tipped with a subulate beak; seed coat rugose.
Prairies and open grounds, Virginia to Missouri, Florida and Texas. Prairie, blue or azure larkspur. May-July.
D. virescens Nutt. Gen. 2: 14. 1818.
D. albescens Rydberg, Bull. Torr. Club 26: 583. 1899.
Perennial, with branched woody roots, pubescent and often somewhat glandular. Stem stout, 1°-3° high; leaf-segments linear, 1"-3" wide; raceme narrow, rather densely flowered; lower pedicels sometimes 2' long, the upper much shorter; flowers white, or bluish-white, finely pubescent; spur horizontal or ascending, 6"-8" long, straight, or slightly curved upward; follicles 6"-9" long, erect, puberulent.
Prairies, Illinois to Minnesota, Manitoba, Kansas and Texas. D. Penardi Huth, of the Rocky Mountains, is closely related to this species. May - July.
Delphinium tricorne Michx. Fl. Bor. Am. 1: 314. 1803.
Stout, glabrous or pubescent, simple, 1°-3° high. Leaves slender-petioled, deeply 5-7-cleft or divided, the divisions linear or obovate, obtuse, entire, or again cleft and toothed; raceme loose, 4' - 5' long, mostly several-flowered; flowers 1'-1 1/2' long, blue or white; spur generally slightly bent, ascending, 10"-15" long; follicles 3, widely spreading, 5"-6" long, tipped with a short beak; seed-coat smooth, dark.
Pennsylvania to the mountains of Georgia, west to Minnesota, Nebraska and Arkansas. Roots tuberous. April-June.