Hemizonia congesta subsp. luzulifolia

(de Candolle) Babcock & H. M. Hall

Univ. Calif. Publ. Bot. 13: 43. 1924.

Common names: Hayfield tarweed
IllustratedEndemic
Basionym: Hemizonia luzulifolia de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 692. 1836 (as luzulaefolia)
Synonyms: Hemizonia congesta var. luzulifolia (de Candolle) Jepson Hemizonia luzulifolia subsp. rudis (Bentham) D. D. Keck
Treatment appears in FNA Volume 21. Treatment on page 293. Mentioned on page 292.

Leaves pubescent, villous, or sericeous (distal with hairs not notably longer at margins), all or distal glandular. Heads in paniculiform arrays. Peduncles 0 or 1–30 mm, bracts not surpassing phyllaries. Calyculi 0. Phyllaries 3.5–6.5 mm, apices usually shorter than bodies. Ray florets 5–11; laminae white, abaxially purple-veined. Cypsela widths 0.5–0.6 times lengths. 2n = 28.


Phenology: Flowering Mar–Dec.
Habitat: Disturbed sites, grassy slopes, valley bottoms, openings in chaparral and woodlands, often clayey soils, serpentine
Elevation: 0–1000 m

Discussion

Subspecies luzulifolia occurs from the North Inner Coast Ranges and northern Great Valley through the San Francisco Bay area to the southern South Coast Ranges. Natural hybridization between subsp. luzulifolia and subsp. lutescens has been reported (E. B. Babcock and H. M. Hall 1924).

Selected References

None.

Lower Taxa

None.
Bruce G. Baldwin +  and John L. Strother +
(de Candolle) Babcock & H. M. Hall +
Hemizonia luzulifolia +
Hayfield tarweed +
0–1000 m +
Disturbed sites, grassy slopes, valley bottoms, openings in chaparral and woodlands, often clayey soils, serpentine +
Flowering Mar–Dec. +
Univ. Calif. Publ. Bot. +
Illustrated +  and Endemic +
Hemizonia congesta var. luzulifolia +  and Hemizonia luzulifolia subsp. rudis +
Hemizonia congesta subsp. luzulifolia +
Hemizonia congesta +
subspecies +