Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Acacia

acacia, wattle
Habit Shrubs or trees [rarely vines], usually unarmed, stipular spines present on A. paradoxa.
Stems

erect to ascending or pendulous, glabrous or pubescent;

twigs not flexuous or slightly so, terete to angled or ridged, short shoots usually absent.
Leaves

alternate (except fascicled or whorled in A. verticillata), even-bipinnate or phyllodic, leaves often modified (in age) to polymorphic phyllodes (enlarged, flattened petiole without leaflets), usually glandular on margins and/or apex, saplings often with even-pinnate juvenile leaves often not present at maturity;

stipules usually present, usually early deciduous, rarely woody, spinose;

petiolate, usually with 1 globose gland;

pinnae [1 or] 2–31[–50] pairs, mostly opposite;

leaflets 8–70 pairs per pinna, opposite, sessile or subsessile, blade margins entire, surfaces glabrous or pubescent.
Inflorescences

20–200+-flowered, terminal or axillary, globose heads or cylindrical spikes, heads solitary, fascicled, or clustered, or arranged in pseudoracemes or pseudopanicles;

bracts present.
Peduncles

usually not elongated in fruit, glabrous or pubescent.
Flowers

mimosoid;

calyx cup-shaped, lobes 4 or 5, triangular, glabrous [pubescent];

corolla yellow to cream, cup-shaped, lobes 4 or 5, triangular, membranous, glabrous [pubescent];

stamens 20–150, rarely connate basally, usually exserted, mostly yellow to gold or creamy white;

anthers dorsifixed, mostly eglandular;

ovary sessile or short-stipitate;

style and stigma filiform.
Fruits

legumes, erect to pendulous, stipitate, stipe usually relatively short, mostly flat, straight to falcate, linear to oblong, apex sometimes beaked, usually dehiscent along sutures, dry, papery to leathery, glabrous or pubescent.
Seeds

usually 6–10, usually flattened, ellipsoid to ovoid, uniseriate, usually with pulpy, bright-colored aril, forming a cap or encircling seed.
x

= 13.

Acacia
Distribution
map from USDA
Indian Ocean Islands; Pacific Islands (Kei Islands, New Guinea); Australia [Introduced in North America; introduced also in South America; introduced elsewhere in tropical and subtropical regions]
[BONAP county map]
Discussion

Species ca. 1300 (15 in the flora).

Acacia species are indigenous mostly in the Southern Hemisphere, with more than 950 in Australia. None is native to the New World.

To preserve as much current usage as possible, at the 17th International Botanical Congress in 2005, the type of the genus Acacia was changed from Acacia scorpioides (Linnaeus) W. Wright to the Australian species Acacia penninervis Sieber ex de Candolle (B. R. Maslin 2008; J. McNeill and N. J. Turland 2010). Presently, there is considerable evidence that the broadly defined genus Acacia is not a natural or monophyletic group (Gill. K. Brown et al. 2008). Therefore, plants of the former Acacia subg. Phyllodineae remain in the genus Acacia (Maslin et al. 2003; Maslin 2008), and other species of the traditional Acacia are transferred to the genera Acaciella, Mariosousa, Parasenegalia Seigler & Ebinger, Pseudosenegalia Seigler & Ebinger, Senegalia, and Vachellia.

Members of Acacia enumerated here are introduced, exotic species proven to be adventive in the United States by vouchered collections; most are restricted to Arizona, southern California, and Florida. In addition, many Australian Acacia species are cultivated in botanical gardens and plant introduction centers and as ornamentals in the nursery trade. Although not clearly established to be adventive, other Acacia species may occasionally be found outside of cultivation; D. Isely (1973) mentioned a few of these, including A. podalyriifolia A. Cunningham ex G. Don, reported from a non-cultivated stand on Santa Catalina Island, California, and more recently from Orange County. Naturalized individuals of A. salicina Lindley and A. stenophylla A. Cunningham ex Bentham are known from Maricopa County, Arizona (ASU). Acacia iteaphylla F. Mueller ex Bentham is naturalized on the University of California-Riverside campus and is possibly invasive (Sanders & Morgan 21588, UCR).

Etymology: Derivation uncertain, perhaps Greek ake or akis, sharp point, alluding to spiny stipules of some species, or a, absent, and kakia, malice, alluding to sacredness or use of wood in making vessels

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Parent taxa Fabaceae > subfam. Caesalpinioideae
Subordinate taxa
A. auriculiformis, A. baileyana, A. cultriformis, A. cyclops, A. dealbata, A. decurrens, A. longifolia, A. mearnsii, A. melanoxylon, A. paradoxa, A. pycnantha, A. redolens, A. retinodes, A. saligna, A. verticillata
Key
1. Leaves compound.
→ 2
2. Leaves with 2–5 pinna pairs; petioles 0–2 mm.
A. baileyana
2. Leaves with (3–)6–31 pinna pairs; petioles 5–33 mm.
→ 3
3. Distance between pinna pairs 7–20 mm; leaflet blades 5–15 mm.
A. decurrens
3. Distance between pinna pairs 2–7 mm; leaflet blades 1.5–5 mm.
→ 4
4. Rachis glands between most pinna pairs.
A. dealbata
4. Rachis glands scattered, at pinna pair nodes and internodes.
A. mearnsii
1. Leaves phyllodic.
→ 5
5. Phyllodes 5–30 mm.
→ 6
6. Stipular spines present.
A. paradoxa
6. Stipular spines absent.
→ 7
7. Phyllodes inequilateral, ± triangular, 5–15 mm wide, alternate.
A. cultriformis
7. Phyllodes acicular, linear, 0.5–1.5 mm wide, fascicled or whorled.
A. verticillata
5. Phyllodes (20–)30–250 mm.
→ 8
8. Phyllodes with pinnate venation.
→ 9
9. Pulvinus 4–8 mm; phyllodes 10–35 mm wide.
A. pycnantha
9. Pulvinus 1–3.5 mm; phyllodes 3–14(–25) mm wide.
→ 10
10. Globose heads 5–7 diam.; phyllode gland not obvious, not disciform.
A. retinodes
10. Globose heads 8–12 mm diam.; phyllode gland obvious, disciform.
A. saligna
8. Phyllodes with parallel venation.
→ 11
11. Inflorescences cylindrical spikes.
→ 12
12. Phyllodes falcate; flowers 5-merous.
A. auriculiformis
12. Phyllodes not falcate; flowers 4-merous.
A. longifolia
11. Inflorescences globose heads.
→ 13
13. Twigs fragrant (vanilla-scented) when crushed, resin-ribbed.
A. redolens
13. Twigs not fragrant when crushed, not resinous.
→ 14
14. Inflorescences pseudoracemes of 2 heads; minor phyllode veins weakly reticulate.
A. cyclops
14. Inflorescences pseudoracemes of 2–8 heads; minor phyllode veins prominently reticulate.
A. melanoxylon
Name authority Miller: Gard. Dict. Abr. ed. 4, vol. 1. (1754) — name conserved
Source FNA vol. 11. Treatment authors: John E. Ebinger, David S. Seigler.
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Boraginaceae and Polemoniaceae.)

The species comparison tool is brought to you by:
Northwest Wildflowers