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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.


Annual, erect, 3–50 cm, generally branched (at least in inflorescence). Leaf: generally alternate (occasionally opposite or whorled), generally sessile, 4–35 mm, 1–3(6) mm wide, thread-like or linear to ovate or obovate, margin gland-toothed or entire; stipular glands present or 0. Inflorescence: generally open or dense cyme, bracted; pedicel thread-like, generally ascending to erect. Flower: sepals lanceolate to ovate, acute or acuminate, glabrous or hairy, or margins glandular-ciliate; petals free, 1–12 mm, yellow, white, or pink, generally with small appendages near base; staminodes 0; carpels 2–3, stigmas linear (± = style in width). Fruit: smooth. Seed: ± triangular in ×-section, acute.
12–13 species: especially California, often on serpentine. (Greek, Latin: western flax) [Sharsmith 1961 Univ Calif Publ Bot 32:235–314] Hesperolinon serpentinum, used in TJM (1993), is not validly published.

Key to Hesperolinon

1. Petals yellow, often veined or tinged orange-red; anthers yellow

2. Leaf base clasping, margin serrate with 1–3 rows of prominent gland-tipped teeth ..... H. adenophyllum

2' Leaf base not clasping, margin neither serrate nor glandular

3. Styles generally 2 (occasionally some plants with both 2- and 3-carpellate flowers) ..... H. bicarpellatum (2)

3' Styles generally 3 (occasionally 2-carpellate flowers in 3-carpellate plants)

4. Styles generally 0.5–1 mm, included; corolla not spreading widely ..... H. clevelandii

4' Styles generally >= 2 mm, exserted; corolla spreading widely

5. Flowers generally clustered at inflorescence tips; stipular glands generally present throughout pl; petals 4–10 mm; filaments 4–8 mm ..... H. breweri

5' Flowers scattered, widely separated throughout inflorescence; stipular glands 0 or present only on proximal stem; petals <= 5.5 mm; filaments <= 4 mm

6. Stem, leaves generally glabrous, or stem puberulent only above nodes; petals 2–4 mm; styles generally 2–3.5 mm ..... H. bicarpellatum (2)

6' Stem, leaves generally puberulent; petals 3.5–5.5 mm; styles generally 3–10 mm ..... H. tehamense

1' Petals white to pink, often veined or tinged darker pink to purple; anthers white to pink or purple

7. Leaves whorled (generally in 4s) on main stem, generally 3–6 mm wide, ovate, margin glandular ..... H. drymarioides

7' Leaves generally alternate on main stem, <= 3 mm wide, thread-like to linear, margins not glandular

8. Styles 2 ..... H. didymocarpum

8' Styles generally 3 (occasionally some 2-carpellate flowers on 3-carpellate plants)

9. Inflorescence generally dense; pedicels generally <= 2 mm at flower (scattered flowers at lower nodes occasionally with pedicels to 5(10) mm), elongating in fruit; stipular glands generally present at leaves, bracts

10. Sepals glabrous; petals white to white flushed or veined with pink ..... H. californicum

10' Sepals hairy; petals light to dark pink ..... H. congestum

9' Inflorescence generally open; pedicels generally 1–25 mm at flower, to 45 mm in fruit; stipular glands 0 or minute, or present only at proximal leaves

11. Styles included; petals only slightly spreading, 0.5–3.5 mm, often <= sepals ..... H. micranthum

11' Styles exserted; petals widely spreading to reflexed, 3–7 mm, > sepals

12. Pedicels straight in bud, not pendent ..... H. disjunctum

12' Pedicels pendent in bud ..... H. spergulinum


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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