Acacia karroo
| Family: | Fabaceae |
| Full name: | Acacia karroo Hayne |
| Location: | Kyffhäuser (2416AD + 2416CB) |
| ID status: | Fairly certain |
| Afrikaans common name(s): | Soetdoring, Karoo doringboom, Doringboom |
| English common name(s): | Sweet-thorn, Mimosa thorn, Cape thorn tree, Karoo-thorn, White thorn |
| Synonym(s): | Acacia capensis (Burm.f.) Burch. Acacia dekindtiana A.Chev. Acacia hirtella E.Mey. Acacia hirtella Willd. var. inermis Walp. Acacia horrida (L.) Willd. accepted by FTA Acacia horrida (L.) Willd. var. transvaalensis Burtt Davy Acacia horrida auct. - sensu Sim (1909), non (L.) Willd. Acacia inconflagrabilis Gerstner Acacia karroo Hayne var. transvaalensis (Burtt Davy) Burtt Davy Acacia reticulata (L.) Willd. Acacia robusta auct. - sensu Oliv. p.p. Acacia seyal auct. - sensu Sim Mimosa capensis Burm.f. Mimosa eburnea auct. - sensu Bojer, non L. Mimosa leucacantha Jacq. Mimosa nilotica auct. - sensu Burm.f., et sensu Thunb., in Fl. Cap. ed. Schult. (1823), non L.-- misapplied name Mimosa reticulata L. |
| Status: | Native |
| Description: | Small to medium-sized tree. The bark of young branches is distinctly orange-red. Thorns are opposite, straight, up to 5 cm long, whitish with dark tips, often inflated along the length. Inflorescences at the ends of new branches, showy. Flowers golden yellow, sweetly scented. Pods slender, sickle-shaped, slightly constricted between the seeds. (from Flora of Zimbabwe website) Shrub, often several stemmed, or a tree to 22 m high, sometimes very slender, spindle-like, and sparsely branched; crown rounded, often irregularly so, or flattened; trunk to 0.75 m diam. Bark dark brown, reddish-brown, brownish-black to black, rough, often fissured, or white to pale greyish-white or greyish-brown and smooth, the latter often with scattered persistent paired spines; young branchlets reddish- to purplish- or blackish-brown, often flaking to expose a rusty-red inner layer, sometimes white to yellowish- or greyish-brown and smooth, glabrous or sometimes sparingly to densely pubescent, eglandular or with small inconspicuous reddish sessile glands. Stipules spinescent, in pairs, usually 0.4-7(10) cm long, sometimes greatly elongated to 25 cm long, the latter usually slightly inflated and up to ±1 cm in diam., remaining distinct to the base and not confluent, straight or sometimes deflexed, whitish or the same colour as the stem, entire plant frequently exceedingly spinescent; other prickles absent. Leaves; petiole 0.5-1.8 cm long, adaxial gland usually present, variable in position, usually rounded or oval, up to 1.5 x 1.5 mm; rhachis (0)1-4.6(9) cm long, glabrous or sometimes sparingly to densely pubescent, with a yellowish- or reddish-brown to black gland at the junction of each of the top 1-3 pinna pairs, between every pinna pair or absent from some; pinnae (1)2-6(13) pairs; rhachillae (1)1.5-3.8(7.2) cm long, glabrous or sometimes densely pubescent; leaflets 5-15(27) pairs per pinna, (2.8)3.5-8(12.5) x 1-2.5(5) mm, linear, linear-oblong to obovate-oblong, eglandular, apex rounded to subacute but not spinulose-mucronate, usually glabrous but sometimes fairly densely pubescent beneath, margins usually without cilia but sometimes spreading cilia present. Inflorescences capitate, on axillary peduncles, fascicled or sometimes solitary, forming terminal racemes, sometimes on lateral axillary branchlets, the entire inflorescence forming an irregular terminal panicle. Flowers bright yellow, sessile; peduncles 0.7-2.4(4) cm long, glabrous or occasionally densely pubescent, sometimes glandular; in-volucel way up the peduncle (when the flowers are young the involucel often appears apical, but as the peduncle lengthens the involucel soon assumes its true position), ±2 mm long. Calyx glabrous throughout or apices of lobes sparingly or sometimes densely pubescent, tube 1.2-1.8 mm long, lobes up to 0.5 mm long. Corolla glabrous or almost so, tube 1.5-2.3 mm long, lobes up to 0.8 mm long, reflexed. Stamen-filaments free, up to 5 mm long; anthers with a deciduous apical gland. Ovary glabrous, up to 1.5 mm long. Pods yellowish- or reddish-brown to brown, (4)5-10.5(21) x 0.5-0.7(1.1) cm, linear, slightly to strongly falcate or sometimes straightish, usually constricted between the seeds, often distinctly moniliform, apex rounded to acuminate, sometimes attenuate at both ends, longitudinally dehiscent, usually longitudinally venose, mostly glabrous but at times densely tomentellous, sometimes inconspicuously glandular. Seeds olive-brown or brown, (3.5)4.5-6.5(9) x (2)3-4(7) mm, elliptic or lenticular, sometimes quadrate, compressed; areole3-5.5(7) x 2-3.5(4.5) mm. (from JSTOR Global Plants website / Flora of Southern Africa) Tree (1.5)3-15 m high, rarely shrubby; bark on trunk dark-red-brown to blackish; young branchlets glabrous or rarely sparsely and inconspicuously puberulous, also with small inconspicuous pale to reddish sessile glands; epidermis flaking off to expose a dark-rusty-red not powdery under-bark, sometimes grey to brown and persistent. Stipules spinescent, up to 7(17) cm long, rather robust, whitish, often deflexed, sometimes fusiform-inflated, up to 1 cm (? or more) thick, but remaining distinct to the base and not confluent; other prickles absent. Leaves with a small to large (sometimes paired) gland at the junction of each pinna-pair, rarely lacking at the basal 1-2 pairs; sometimes a large gland on the upper side of the petiole; pinnae (1)2-7(9) pairs; leaflets 5-15 (27) pairs, 4-7(12) x 1-3(5.5) mm, glabrous or rarely with minutely ciliolate margins, eglandular, obtuse to subacute but not spinulose-mucronate at the apex; lateral nerves invisible beneath. Flowers deep- or golden-yellow, in axillary pedunculate heads 8-12 mm in diam. borne along shoots of the current season, sometimes aggregated into leafless terminal 'racemes'; involucel c. 1/3-3/4-way up the peduncle, c. 2 mm long. Calyx 1.25-2 mm long, subglabrous. Corolla c. 2.5-3 mm long, glabrous or almost so. Pods dehiscent, (4)6-16 x 0.6-0.9(1) cm, linear, falcate, usually constricted (sometimes not) between the seeds, glabrous except for small usually inconspicuous glands. Seeds olive-green to -brown, 5-8 x 3-5 mm, oblong-elliptic, compressed; areole 4.5-5.5 x 2-3.5 mm. (from JSTOR Global Plants website / Flora Zambesiaca) |
| Link(s) |
African Plant Database
JSTOR Plant Science Kew Herbarium Catalogue BGBM Berlin-Dahlem - Virtual Herbarium Züricher Herbarien iNaturalist (Namibia / Alex Dreyer) iNaturalist (Namibia) iNaturalist (southern Africa) Flora of Zimbabwe Fleurs de notre Terre - Galerie Namibie Tree Atlas of Namibia |
| Photographer: | AA Dreyer |
| Date of photograph: | 18 Dec 2009 |
| Camera make: | Canon |
| Camera model: | PowerShot A700 |
| Lens aperture: | f/4.0 |
| Shutter speed: | 1/640 s |
| ISO speed: | - |
| Content last updated: | 18 Apr 2024 |
