Amsonia tabernaemontana Walter

Blue Star


CC = 6
CW = -3
MOC = 42

© DETenaglia

Family - Apocynaceae

Habit - Perennial forb, sometimes woody near base.

Stems - Ascending to erect, to 1.1 m, usually multiple from base, sometimes branching near tips, with milky sap, glabrous.

Amsonia_tabernaemontana_stem.jpg Stem and node.

© DETenaglia

Leaves - Alternate, short-petiolate, (becoming sessile near base of plant), simple, entire. Petioles to 1 cm. Blades lanceolate to ovate, sharply pointed, 6-15 cm long, 2-5 cm wide, dull green on upper surface, slightly glaucous below, mostly glabrous. Margin ciliate.

Amsonia_tabernaemontana_leaves.jpg Leaves.

© DETenaglia

Amsonia_tabernaemontana_leaf2.jpg Leaf abaxial.

© SRTurner

Amsonia_tabernaemontana_leaves2.jpg Stem and leaves.

Leaves lack the glossiness characteristic of shining blue star (A. illustris).

© SRTurner

Inflorescence - Terminal clusters, 7-12 cm long at flowering, positioned near the leaf tops. Flower stalks 2-7 mm long.

Amsonia_tabernaemontana_inflorescence.jpg Inflorescence.

© SRTurner

Flowers - Calyces 5-lobed, the lobes triangular, the tube to 1 mm long, glabrous. Corollas densely hairy internally, sparsely to moderately hairy toward the tip externally, the tube 7-8 mm long, about 1.5 mm wide at base, the throat 2.5-3.5 mm wide, the lobes 5-8 mm long, 1.2-2.0 mm wide, light blue. Stamens 5, alternating with corolla lobes, adnate to corolla tube near apex. Anthers yellow-orange. Style glabrous, 4.5mm long. Stigma capitate, winged at base. Carpels 2, seeds many.

Amsonia_tabernaemontana_calyx2.jpg Calyces.

© SRTurner

Amsonia_tabernaemontana_flower.jpg Corolla.

© DETenaglia


© SRTurner

Fruits - Slender follicles to 12 cm long, terete, many seeded, glabrous, erect at maturity, positioned among the leaves, not constricted between the seeds. Seeds 8-10 mm long, the surface usually with low, corky ridges and tubercles.

Amsonia_tabernaemontana_fruits.jpg Fruits.

© SRTurner

Flowering - April - May.

Habitat - Open woods, thickets, slopes, ravines, roadsides, railroads.

Origin - Native to the U.S.

Lookalikes - A. illustris.

Other info. - This striking species can be found in scattered locations in the southern half of Missouri and also in a handful of counties around the St. Louis area. It ranges throughout most of the southeastern U.S. The plant is easy to identify because of its many blue flowers and broad, pale leaves. This species also bleeds a milky sap when injured. It is very similar to Amsonia illustris, but unlike that species has erect fruits and leaves which are not glossy.

The species has been subdivided into varieties, two of which are currently recognized in Missouri. Variety salicifolia has relatively narrow leaves, to 3 cm wide, and is the most common variety in the state. Variety tabernaemontana has wider (ovate) leaves. The natural ranges of these forms in Missouri have been obscured by escapes from ornamental cultivation and by habitat restoration plantings.

Photographs taken off County Road 40 in the Lowndes Wildlife Management Area, Lowndes County, AL., 4-9-05 (DETenaglia); also at Duck Creek Conservation Area, Bollinger County, MO, 5-18-2014 (SRTurner).