Amsonia tomentosa
Amsonia jonesii
gray amsonia, woolly bluestar
Jones' bluestar
erect, 11–65 cm, glabrous or tomentose;
branches usually borne on most of stem (occasionally confined to distal portion), well exceeding infructescence.
erect, (15–)23–60(–77) cm, glabrous or sparsely to moderately short-pubescent;
branches few, confined to distal part of stem, usually remaining shorter than infructescence, or occasionally absent.
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.
petiole 1–3(–4.5) mm, glabrous (base pubescent);
blades heteromorphic;
stem leaf blades ovate, especially proximally, to lanceolate (elliptic, rarely narrowly elliptic), (2–)3.3–5.5(–6.1) cm × (6–)9–25(–32) mm, margins entire, not revolute, not ciliate, apex slightly acuminate (acute), surfaces glabrous;
branch leaf blades lanceolate (narrowly elliptic), 2.2–3.9 cm × 3–9(–10) mm.
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.
sepals narrowly deltate to deltate (subulate, broadly deltate), (0.3–)1–2.5(–4) mm;
corolla tube blue, (6–)7.5–8.5(–10) mm, lobes blue, (4–)5–7(–8.5) mm, outer surface of corolla glabrous or bearing villous patches on apical part of tube and basal part of lobes.
(8–)11–17 × (3–)3.9–5.5(–6.3) mm.
6–10 × 1.5–2.5 mm.
erect (aberrantly deformed and spreading), 2–8(–9.5) cm × (4–)4.8–6.8 mm, apex acuminate, glabrous (partly tomentose).
erect, (1.4–)3.5–6.5(–9) cm × (2.5–)3–4.3(–4.8) mm, apex short-acuminate to acute, glabrous.
Amsonia tomentosa
Amsonia jonesii
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.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Amsonia jonesii is readily distinguished from other species in its subgenus by its short and relatively broad, often ovate leaves, small blue flowers with usually short sepals (subtended by short, broad bracts), and few, short, or sometimes absent stem branches. Its range extends farther north than that of any other species of subg. Sphinctosiphon. In Arizona, it is confined to Coconino and Mojave counties. A specimen from Utah representing a probable hybrid involving A. jonesii (Thorne & Thorne s.n., ARIZ) has unusually narrow leaves and multiple well-developed branches on each stem.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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. | 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. | var. stenophylla |
CA
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