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..
Annual or perennial erect branching herbs, with racemose or paniculate showy flowers. Leaves palmately lobed or divided. Sepals 5, the posterior one prolonged into a spur. Petals 2 or 4, small, the two posterior ones spurred, the lateral, when present, small. Carpels few, sessile, many-ovuled, forming follicles at maturity. [Latin, from the supposed resemblance of the flowers to a dolphin.]
A genus of beautiful plants, with large irregular flowers, comprising some 125 species, natives of the north temperate zone. Besides the following, many others grow in western North America and several in the mountains of Mexico. Type species: Delphinium Consolida L.
Delphinium Consólida L., a European species which has a glabrous style and capsule, is widely recorded as naturalized in the eastern United States, and was admitted into our first edition; but all specimens examined prove to be D. Ajacis.
Annual; pistil 1; plant pubescent. | 1. | D. Ajacis. |
Perennials; pistils 3. | ||
Follicles erect or nearly so. | ||
Leaf-segments broadly cuneate-obovate or cuneate-oblanceolate; plant glabrous. | ||
2. | D. exaltatum. | |
Leaf-segments linear. Panicle pyramidal; plant glabrous. | 3. | D. Treleasei. |
Panicle narrow; plants pubescent or puberulent, at least above. | ||
Raceme open; roots tuberous. | 4. | D. Nelsoni. |
Raceme strict; roots not tuberous. | ||
Flowers bright blue: bractlets close to the calyx. | 5. | D. carolinianum. |
Flowers bluish-white; bractlets distant from the calyx. | 6. | D. virescens. |
Follicles widely divergent. | 7. | D. tricorne. |

Fig. 1870
Delphinium Ajacis L. Sp. Pl. 531. 1753.
Annual, finely pubescent, somewhat branched, 3° high or less, usually branched. Leaves finely dissected into narrowly linear, acutish segments, mostly less than 1" wide, or those of the lower leaves somewhat wider; lower leaves petioled, the upper sessile or nearly so; flowers racemose; racemes short or elongated, sometimes 10' long, the pedicels 1/4'-1' long; flowers blue, rarely white; spur slender, somewhat curved, about 1' long; pistil 1; style pubescent; follicle erect, pubescent, beaked.
Fields, meadows and waste grounds, Nova Scotia to South Carolina, Montana and Kansas. June-Aug.
 
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