Delphinium virescens Nutt. - Prairie Larkspur

Delphinium virescens plant

Family - Ranunculaceae

Stems - To +70cm tall, erect, typically simple, herbaceous, pubescent to pannose or glandular pubescent, from fibrous roots and a small caudex.

Delphinium virescens stem

Leaves - Alternate, petiolate below to sessile above. Petioles to +/-7cm long, pubescent. Blades 3-lobed, to +5cm long and broad. Each lobed divided again. Ultimate divisions linear to linear-oblong, 2mm broad, pubescent, entire.

Delphinium virescens leaves

Inflorescence - Terminal spikiform raceme to +30cm tall(long). Pedicels to 1.3cm long in flower, elongating in fruit to -3cm long, densely pubescent to densely pannose, often with pair of small subopposite bracts in upper 1/4. Each pedicel subtended by an attenuate bract to 1.5cm long, 2mm broad at base, reduced above.

Flowers - Sepals white to pale lilac. Upper sepals spurred. The spur to 1.8cm long, dense pubescent to pannose. All sepals pubescent to pannose externally, with brownish spot near apex. Petals 4. The upper two petals spurred, white to pale lilac, darker near base of spur. Lateral petals bearded. Stamens many(+/-20). Filaments flattened and broad at base, lilac below to whitish, 6-7mm long, glabrous. Anthers purple to brownish, 1.2mm long. Carpels 3, pubescent. Fruits erect, pubescent to pannose, 2cm long, terete. Seeds many(+10), with scaly projections to 3mm long.

Delphinium virescens flower

Delphinium virescens fruitDeveloping fruits.

Flowering - May - July.

Habitat - Prairies, rocky open woods, railroads.

Origin - Native to U.S.

Other info. - Although I have this plant listed as a separate species, following what Steyermark had in his book in 1963, the plant is now considered to be a subspecies of Delphinium carolinianum. The correct name is now D. carolinianum ssp virescens. This subspecies has white flowers, whereas D. carolinianum ssp carolinianum has blue flowers. Where the two subspecies overlap in range they integrade. The resulting plants can have light blue flowers as shown below:

Delphinium carolinianum flower

Photographs taken in Lebanon, TN., 5-16-03, and at Taberville Prairie, MO., 6-7-03.


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