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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.



Tracey Slotta

Generally shrub, generally erect; hairs sparse to dense, stellate (stalked or sessile), simple, and glandular. Leaf: petioled; blade unlobed to 3–7-lobed, coarsely or shaggy-hairy to tomentose. Inflorescence: head- to panicle-like, flowers generally > 1 in leaf axils; bracts leaf-like or not, in involucre or not; bractlets 3, free, linear to lanceolate, persistent. Flower: calyx 5-lobed; petals 5, pale pink-purple or white (often ± purple when dry); petals generally > calyx, fused at base; stamens open prior to stigma maturation; style branches 5–14. Fruit: segments 5–14, 2–5 mm, separating, dehiscent, smooth, top hairy, beak 0. Seed: 1 per segment, brown to black.
12 species: California, northwestern Mexico. (Greek: soft shrub) Malacothamnus foliosus (S. Watson) Kearney reported but evidently not documented for California.
Unabridged etymology: (Greek: malakos, soft, thamnos, shrub)
Unabridged references: [Kearney 1951 Leafl W Bot 6:93–131; Fryxell 1988 Syst Bot Monogr:270–274]

Key to Malacothamnus

1. Inflorescence head-like ..... M. palmeri

2. Involucre bracts 20 mm wide, often > petals; leaf ± glabrous adaxially ..... var. involucratus

2' Involucre bracts 12–13 mm wide, ± = petals; leaf hairy adaxially ..... var. palmeri

1' Inflorescence spike- or panicle-like

3. Inflorescence spike- or panicle-like

4. Hairs white; branches ± erect

5. Branches slender; leaves 3–5-lobed; flowers < 10 per node ..... M. clementinus

5' Branches stout; leaves shallowly 5-lobed; flowers 3–5 per node ..... M. fremontii

4' Hairs ± yellow; branches spreading or ± erect

6. Branches slender; leaves thin

7. Leaves sparsely short-hairy adaxially, long-shaggy-hairy abaxially, 3–5-lobed; flowers generally >= 10 per node; flowering stalks 10–15 mm; calyx hairs <= 3 mm ..... M. densiflorus

7' Leaves densely hairy, unlobed to ± 3–5-lobed; flowers 3–6 per node; flowering stalks < 4 mm; calyx hairs < 1 mm ..... M. marrubioides

6' Branches stout; leaves thick

8. Leaf 3–5-lobed, abaxially veins ± not raised, hairs not denser; flowers generally ± 10 per node; leaf-like bracts many ..... M. aboriginum

8' Leaf unlobed to obscure-3-lobed, abaxially veins raised, hairs denser; flowers 3–6 per node; leaf-like bracts 3–5 ..... M. orbiculatus

3' Inflorescence panicle-like

9. Hairs ± yellow; stellate hairs with < 10 rays ..... M. davidsonii

9' Hairs white; stellate hairs with > 25 rays

10. Bractlets black in age ..... M. jonesii

10' Bractlets not black in age

11. Branches spreading or ± erect

12. Leaf blade < 5 cm, veins prominent abaxially, hairs adaxially ± = abaxially ..... M. abbottii

12' Leaf blade <= 7 cm, veins ± prominent abaxially, hairs adaxially < abaxially ..... M. hallii

11' Branches spreading ..... M. fasciculatus

13. Calyx lobes deltate to cordate; stellate hairs with long rays, especially on leaves abaxially; flowering stalks stout ..... var. catalinensis

13' Calyx lobes awl-shaped to lanceolate; stellate hairs with short rays; flowering stalks slender

14. Leaf hairs adaxially ± = abaxially; filament column ± 1/2 petals ..... var. fasciculatus

14' Leaf hairs ± 0 or adaxially > abaxially; filament column > 1/2 petals

15. Leaves thick, blade < 7 cm, shallowly lobed, adaxially ± glabrous ..... var. nesioticus

15' Leaves thin, blade < 8 cm, deeply lobed, adaxially ± hairy ..... var. nuttallii


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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