Amsonia tomentosa
Amsonia tharpii
gray amsonia, woolly bluestar
feltleaf bluestar
erect, 11–65 cm, glabrous or tomentose;
branches usually borne on most of stem (occasionally confined to distal portion), well exceeding infructescence.
usually erect (rare long stems always ascending), 10–20(–50) cm, moderately (sparsely) pubescent;
branches usually borne on distal portion, seldom to near base of stem, equaling or slightly exceeding infructescence.
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 0.5–2 mm, sparsely to moderately pubescent (glabrous or densely pubescent);
blades heteromorphic;
stem leaf blades narrowly oblong-elliptic, lanceolate, narrowly lanceolate, or narrowly elliptic to ligulate (markedly narrower towards distal part of stem), 2.5–5(–7.5) cm × (2–)4–10(–13) mm, margins entire, not revolute, sometimes ciliate, apex acute, surfaces sparsely pubescent abaxially primarily on midrib (or glabrous);
branch leaf blades very narrowly lanceolate to very narrowly oblong or linear, 2–5.5 cm × 1–3 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 subulate to narrowly deltate, (2–)3–5(–6) mm, usually ciliate;
corolla tube purplish, (11–)12–17 mm, lobes white to greenish white or pale blue, (5–)6–9(–12) mm, outer surface of corolla glabrous.
(8–)11–17 × (3–)3.9–5.5(–6.3) mm.
7–11 × 2–3 mm.
erect (aberrantly deformed and spreading), 2–8(–9.5) cm × (4–)4.8–6.8 mm, apex acuminate, glabrous (partly tomentose).
erect, 2–7(–12) cm × 2.5–5 mm, apex acuminate, glabrous.
Amsonia tomentosa
Amsonia tharpii
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.)
The U.S. Fish & Wildlife Service concluded in 2009 that Amsonia tharpii should be considered for listing as federally threatened or endangered due to its limited range and threats from grazing and development, although no formal action has been taken. It is listed as endangered in New Mexico. Collections were seen only from Eddy County in southeastern New Mexico and Pecos County in western Texas. This species is notable for its usually small size and the frequent appearance of pubescence at the base of the adaxial surface of the corolla lobes, which is an extension of the indument inside the corolla tube.
(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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