Stems erect, 11–65 cm, glabrous or tomentose; branches usually borne on most of stem (occa­sionally confined to distal por­tion), well exceeding infruc­tes­cence. Leaves: petiole 1–5 mm, glabrous or tomentose (leaves rarely sessile); leaf blades slightly or moderately hetero­morphic; stem leaf blades ovate to narrowly lanceolate, narrowly to very narrowly elliptic, or elliptic, (2–)3–5(–6) cm × (3–)4–27 mm, margins entire, not revolute, not ciliate, apex acute (somewhat acuminate), surfaces glabrous or densely (rarely sparsely) tomentose; branch leaf blades narrower than stem leaf blades, (2.2–)3–4.7(–5.6) cm × (2–)3–6(–13) mm. Flowers: sepals subu­late or narrowly deltate (deltate), (2–)3.5–6(–7.5) mm; corolla tube green to purplish or pinkish green, (7–)8–12(–13) mm, lobes bluish (violet- to lavender-tinged) to white especially after anthesis (pinkish, bluish, or purple-tinged), (2.8–)4.5–8 mm, outer surface of corolla glabrous. Follicles erect (aberrantly deformed and spreading), 2–8(–9.5) cm × (4–)4.8–6.8 mm, apex acu­minate, glabrous (partly tomentose). Seeds (8–)11–17 × (3–)3.9–5.5(–6.3) mm.

Distribution

sw United States.

Discussion

Varieties 2 (2 in the flora).

Both varieties of Amsonia tomentosa have an unusual pattern of variation in pubescence. Stems and leaves are usually either densely tomentose or glabrous, with intermediate density of pubescence rare. In some populations, the two forms are found together, suggest­ing that indument may be a single-gene trait.

Selected References

None.

Lower Taxa

Amsonia tomentosa var. stenophylla, Amsonia tomentosa var. tomentosa

Key

1	Stem leaf blades ovate to lanceolate (narrowly elliptic to elliptic), (6–)8–27 mm wide, branch leaf blades markedly narrower, 4–13 mm wide; w, s Arizona, California, Nevada.	Amsonia tomentosa var. tomentosa
1	Stem leaf blades narrowly to very narrowly elliptic or narrowly lanceolate, (3–)4–8(–10) mm wide, branch leaf blades slightly narrower, (2–)3–6(–7) mm wide; n Arizona, Utah.	Amsonia tomentosa var. stenophylla