Amsonia subg. Articularia

Stems usually branched for most of length (occasionally only distally). Bracts on distal portions of inflorescences linear to narrowly deltate, mostly 2–6 mm (seldom less than 2 mm). Flowers: corolla tube (7–)8–12(–13) mm, moderately to strongly constricted just below apex, often in distinct narrow band (most visible just before anthesis); stigma apiculate with 2 small lobes. Follicles moniliform, strongly constricted between seeds. Seeds light reddish brown to pale brown, fusiform with acute to rounded-acute or flat-truncate (rarely diagonally truncate) ends, mostly smooth except at ends and with a prominent longitudinal groove.

Distribution

sw, sc United States, n Mexico.

Discussion

Species 2 (2 in the flora).

Within subg. Articularia, as many as four species, one with two varieties, have been recognized. The most recent revision (S. P. McLaughlin 1982) recognized only one species with two varieties.

Selected References

None.

Lower Taxa

Amsonia arenaria, Amsonia tomentosa

Key

1	Stem leaf blades linear (ligulate or very narrowly elliptic), 1.6–3.5(–5.5) mm wide, surfaces moderately to sparsely tomentose; flowers purple to magenta, maroon, or lavender (blue); New Mexico, Texas.	Amsonia arenaria
1	Stem leaf blades ovate to narrowly lanceolate, narrowly to very narrowly elliptic, or elliptic, (3–)4–27 mm wide, surfaces glabrous or densely (rarely sparsely) tomentose; flowers bluish (violet- to lavender-tinged) to white (pinkish, bluish, or purple-tinged); Arizona, California, Nevada, Utah.	Amsonia tomentosa