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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.

 

ACACIA

David Seigler & John E. Ebinger


Shrub, tree, armed or not; generally evergreen. Leaf: even-2-pinnate or, if simple, true blades 0, petioles, main axes blade-like, with 1 prominent midvein or >= 2 generally prominent longitudinal veins; generally alternate, generally with a swollen, joint-like thickening at base that governs orientation, main axis with raised glands or not. Inflorescence: head, generally axillary, 1 or in raceme or panicle, or flowers in spike; staminate flowers often present. Flower: radial; sepals, petals 4–5, inconspicuous; stamens many, conspicuous, exserted, free; ovary simple. Fruit: generally dehiscent, occasionally tardily so, flat or ± cylindric. Seed: aril generally enlarged, forming cap or completely encircling seed.
± 960 species: tropics, subtropics, especially Australia. (Greek: sharp point) [Orchard & Wilson 2001a, 2001b, (eds) Fl Australia. Vol 11. Mimosaceae, Acacia, part A and B. ABRS] Recognition of Acacia, Senegalia (including Acacia greggii), Vachellia (including Acacia farnesiana) current consensus; many Australian species cultivated, including Acacia cultriformis G. Don, Acacia elata Benth., some naturalized, spreading in California.
Unabridged references: [Orchard & Wilson 2001a, 2001b, (eds) Flora of Australia. Volume 11. Mimosaceae, Acacia, part A and B. Melbourne]

Key to Acacia

1. Leaves 2-pinnate

2. 1° leaflets 2–5 pairs ..... A. baileyana

2' 1° leaflets generally > 6 pairs (3–13)

3. Twigs winged; 2° leaflets >= 10 mm ..... [A. decurrens]

3' Twigs angled; 2° leaflets < 7 mm

4. Leaf main axis with raised glands at each 1° leaflet pair; fruit glabrous, silver-blue ..... A. dealbata

4' Leaf main axis with raised glands at most 1° leaflet pairs and generally between; fruit ± hairy, dark brown ..... [A. mearnsii]

1' Leaves simple

5. Leaf < 40 mm

6. Stipular spines present; heads 1 ..... [A. paradoxa]

6' Stipular spines 0; heads in racemes

7. Leaf > 4 mm wide, tip not spine-like ..... [A. podalyriifolia]

7' Leaf <= 1.5 mm wide, tip spine-like ..... [A. verticillata]

5' Leaf generally > 40 mm

8. Leaf with 1 prominent midvein

9. Petiole base 4–8 mm; raceme, occasionally panicle of 10–30 heads ..... [A. pycnantha]

9' Petiole base <= 4 mm; raceme of 2–9 heads

10. Leaf narrowly lanceolate; head 5–7 mm wide; gland above petiole base not obvious, < 1 mm wide ..... [A. retinodes]

10' Leaf linear to narrowly elliptic; head 8–12 mm wide; gland above petiole base obvious, 1–2 mm wide ..... A. saligna

8' Leaf with >= 2 ± prominent longitudinal veins

11. Flowers in spikes ..... A. longifolia

11' Flowers in heads, these 1 or in racemes or panicles

12. Leaves, stems resinous, vanilla-scented when crushed ..... A. redolens

12' Leaves, stems not resinous, not vanilla-scented when crushed

13. Shrub, branches dense, spreading from base; leaf narrowly oblong to obovate, generally 4–15 mm wide ..... A. cyclops

13' Tree, generally with 1 trunk; leaf (except juvenile) lanceolate to oblanceolate, generally 6–30 mm wide ..... A. melanoxylon

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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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