Xylorhiza tortifolia

(Torrey & A. Gray) Greene

Pittonia 3: 48. 1896.

IllustratedEndemic
Basionym: Haplopappus tortifolius Torrey & A. Gray Boston J. Nat. Hist. 5: 109. 1845 (as Aplopappus)
Synonyms: Machaeranthera tortifolia (Torrey & A. Gray) Cronquist & D. D. Keck
Treatment appears in FNA Volume 20. Treatment on page 409. Mentioned on page 407, 408.

Subshrubs, 20–60(–80) cm. Stems branched mostly in proximal 3/4, ± piloso-villous, stipitate-glandular. Leaf blades lanceolate to elliptic-oblong or oblanceolate, 3–20(–25) mm wide, bases often subclasping or sometimes attenuate and not clasping, margins flat, sharply spinulose-toothed, faces loosely villous or glabrous, stipitate-glandular. Peduncles 5–25 cm. Involucres 12–20 × 15–20(–30) mm. Ray florets (15–)18–60(–85); corollas usually lavender, seldom white. Style-branch appendages shorter than stigmatic lines.

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Key

1 Stems, leaves, and involucres glabrous, stipitate-glandular; leaf margins sparsely piloso-villous to puberulent Xylorhiza tortifolia var. imberbis
1 Stems, leaves, and involucres piloso-villous to puberulent, finely stipitate-glandular Xylorhiza tortifolia var. tortifolia