Pentachaeta exilis

(A. Gray) A. Gray

Proc. Amer. Acad. Arts 8: 633. 1873.

Common names: Meager pentachaeta
Basionym: Aphantochaeta exilis A. Gray in War Department [U.S.], Pacif. Railr. Rep. 4(5): 100, plate 11[as 10]A. 1857
Synonyms: Chaetopappa exilis (A. Gray) D. D. Keck
Treatment appears in FNA Volume 20. Treatment on page 47. Mentioned on page 46.

Plants 2–6 cm. Stems simple or branched, rarely with many branches from bases. Leaf blades linear to filiform, 12–32 × 0.5–1 mm. Involucres turbinate to campanulate. Phyllaries in 2(–3) series, elliptic to obovate, glabrous or sparsely and minutely glandular. Ray (or pistillate) florets 0 or 1–5; corollas white, laminae 0.8–2 mm, or 0, or apiculum 0.1–0.5(–1) mm. Disc florets 3–6(–15); corollas yellowish to reddish, club-shaped, widened through limbs, abruptly contracted at lobes, lobes 5, (lobes and sometimes distalmost portion of limbs) yellow or purplish red at maturity, style branches (0.7–)1–2 mm, stigmatic portions 0.4–0.5 mm. Pappi 0, or of (3–)5 bristles, not dilated at bases. 2n = 18.


Subspecies 2 (2 in the flora).

Plants of Pentachaeta exilis with greatly reduced or completely absent pappi apparently are scattered over the range of the species. This feature is relatively constant within a population.

Selected References



1 Ray (pistillate) corollas elaminate or with apiculum 0.1–0.5(–1) mm; disc florets 3–6(–15), corolla lobes red-purple, style branches (0.7–)1–2 mm, stigmatic portions 0.4–0.5 mm Pentachaeta exilis subsp. exilis
1 Ray (pistillate) corollas laminate, laminae 0.8–2 mm; disc florets (7–)15–34, corolla lobes yellow, style branches 2–3 mm, stigmatic portions 0.6–1mm Pentachaeta exilis subsp. aeolica