|University of California, Berkeley|
|Directory News Site Map Home|
Key to families | Table of families and genera
This text currently parallels The Jepson Manual: Vascular Plants of California, Second Edition that is now available at the University of California Press.
Text appearing in blue on this page will not appear in the printed book; it will be displayed only on the Web. 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 to small tree; monoecious.
Leaf: simple, opposite or alternate, generally petioled, entire to 1–4-pinnately lobed or divided, distal-most often reduced, bract-like.
Inflorescence: staminate heads and pistillate heads together in distal leaf axils or in terminal, spike-like clusters, or staminate heads in spike- or raceme-like clusters distal to pistillate heads; staminate involucre ± cup-shaped, phyllaries in 1 series, ± fused, receptacle flat or rounded, paleate; pistillate phyllaries 0 or few, in 1 series, free, ± thin, receptacle paleate, palea bases fused, becoming a hard bur with each pistillate flower in a separate chamber, tips (occasionally not evident in flower heads) becoming hard knobs, spines, or scarious wings.
Pistillate flower: 1–5; corolla 0; style branches elongated.
Staminate flower: 3–many; corolla translucent to yellow or red-purple; filaments fused, anthers free; style unbranched, ovary vestigial, pappus 0.
Fruit: inside bur with beak(s) surrounding style(s); pappus 0.
45–50 species: native to Am, especially sw US, n Mex. (Greek: early name for aromatic plants; mythic food of the gods) [Strother 2006 FNANM 21:10–18] Wind-blown pollen often allergenic.
Unabridged note: Spines of bur derived from paleas, not phyllaries.
1. Lf blade linear to thread-like or lobes thread-like; free palea tips of bur becoming flat, membranous, wings
2. Wings of bur 0.5–2 mm wide
3. Wings of bur in 1 whorl, ± acute to widely obtuse; leaves lobed or generally entire, abaxially generally glabrous; flowers fall ..... A. monogyra
3' Wings of bur spiraled, spine-tipped; leaves generally lobed, abaxially strigose; flowers spring ..... [A. ×platyspina]
2' Wings of bur 2.5–8 mm wide — flowers in spring ..... A. salsola
4. Wings generally 5–9, generally 2.5–4 mm, 2.5–5 mm wide, spreading from bur body in ± 1 central whorl-like spiral; pistillate head phyllary generally 1, obovate, transparent ..... var. pentalepis
4' Wings generally 10–13, generally 3.5–5.5 mm, 3.5–6.5(8) mm wide, spiraled around bur body, spreading or ascending and enwrapping bur; pistillate head phyllaries generally several, ovate, green or transparent, ± hairy ..... var. salsola
1' Lf blade linear to round, variously toothed or lobed; free palea tips of burs knob-like or spiny, or not evident
5. Shrub — stems persisting 2+ seasons
6. Bur spines straight, flat or round in ×-section
7. Lf blade 1–3 × pinnately lobed or divided; bur puberulent ..... A. dumosa
7' Lf blade coarsely toothed or pinnately lobed; bur densely long-soft-hairy ..... A. eriocentra
6' Bur spines hooked, round in ×-section
8. Cauline leaves sessile, ± clasping, spine-tipped and spiny-dentate ..... A. ilicifolia
8' Cauline leaves petioled, generally toothed or lobed but not spiny
9. Lf blades lance-triangular, (3)5–20 cm; bur ellipsoid, body finely glandular ..... A. ambrosioides
9' Lf blades ± ovate, 1–3 cm; bur ± spheric, body densely woolly ..... A. chenopodiifolia
5' Annual or perennial herb
10. Annual from slender taproot
11. Lf blade unlobed or palmately 3–5-lobed ..... [A. trifida]
11' Lf blade 1–4 × pinnately lobed or divided
12. Bur spines 0–30, spiraled, sharply pointed; distal staminate phyllary tips ± black-lined ..... A. acanthicarpa
12' Bur spines 4–12, in ± 1 whorl below beak, generally blunt; staminate phyllary tips uniformly green ..... A. artemisiifolia
10' Perennial from rhizome-like roots or taprooted caudex
13. Bur spines many, spiraled
14. Sts forming mat on coastal dunes; bur 5–10 mm; spines straight ..... A. chamissonis
14' Sts erect; bur 2–5 mm; spines hooked ..... A. confertiflora
13' Bur spines 0–few, generally on distal 1/2
15. Lf coarsely toothed or generally 1–2 × pinnately lobed or divided; plant generally 3–20 dm ..... A. psilostachya
15' Lf 2–4-pinnately divided into many minute segments; plant generally 1–3.5 dm ..... A. pumila
Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [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].
We encourage links to these pages, but the content may not be downloaded for reposting, repackaging, redistributing, or sale in any form, without written permission from The Jepson Herbarium.