Arquita E. Gagnon, G. P. Lewis & C. E. Hughes, Taxon 64(3): 479. 2015

Gagnon, Edeline, Bruneau, Anne, Hughes, Colin E., de Queiroz, Luciano Paganucci & Lewis, Gwilym P., 2016, A new generic system for the pantropical Caesalpinia group (Leguminosae), PhytoKeys 71, pp. 1-160 : 69-71

publication ID

persistent identifier

treatment provided by

PhytoKeys by Pensoft

scientific name

Arquita E. Gagnon, G. P. Lewis & C. E. Hughes, Taxon 64(3): 479. 2015


24. Arquita E. Gagnon, G. P. Lewis & C. E. Hughes, Taxon 64(3): 479. 2015 Figs 38 View Figure 38 , 39I-O View Figure 39


Arquita mimosifolia (Griseb.) E. Gagnon, G. P. Lewis & C. E. Hughes.


Small to medium-sized, often decumbent shrubs, 0.3-2.5 m in height, slender in stature, usually with glandular trichomes on various parts of the plant; young stems and inflorescence rachises red-orange to maroon. Stipules ovate-obovate to deltoid, chartaceous, 2.5-5.5 mm long, usually with a fimbriate-glandular margin and short-stalked glands (except in some specimens of Arquita ancashiana ), caducous. Leaves bipinnate, with 1-5 pairs of pinnae, usually with a single terminal pinna; petiole (0.3-) 0.5-6 cm long; rachis 0.5-6 cm long (but sometimes absent); leaflets in 4-12 opposite pairs per pinna, oblong-obovate, 2.5-10 (- 14) × 1-3.5 (- 6) mm, often with maroon/black glands in depressions on crenulated leaflet margins, and sometimes with occasional sessile black glands on the undersurface of leaflet blades (in Arquita ancashiana the glands are submarginal on the lower half of the basal leaflets of the pinnae). Inflorescences leaf-opposed, determinate racemes (with only 1 to 2 flowers open at a given time), (5-) 7-21 (- 41.5) cm long; bracts lanceolate, acuminate, either eglandular or covered in gland-tipped trichomes, 2.75-7 mm long, caducous. Flowers bisexual, zygomorphic; calyx comprising a hypanthium, and 5 sepals, 6-11 mm long, caducous, the lower sepal cucullate, and sepals either have an entire or glandular-fimbriate margin; petals 5, free, yellow to orange, median petal, sometimes streaked red, 6-17 × 4-12 mm, claw pubescent at the base, either flat or inrolled, sometimes with stipitate-glandular trichomes on the dorsal surface of the whole petal, upper and lower lateral petals 6-17 × 3-12 mm; stamens 10, free, 5-13 mm long, anthers 0.75-2.3 mm long, the stamens deflexed and loosely grouped around the gynoecium; ovary usually covered with gland-tipped trichomes. Fruits laterally compressed, lunate-falcate pods with a marcescent style, covered sparsely to densely with gland-tipped trichomes, these sometimes dendritic, 2-4.7 × (0.7-) 0.9-1 cm. Seeds laterally compressed, ovate-orbicular, 4.5-6 × 3.5-4.5 × 1 mm, the testa shiny olive-grey, sometimes mottled or streaked black.

Geographic distribution.

The genus Arquita comprises six taxa in five species restricted to the Andes in South America, in disjunct inter-Andean valleys, in Ecuador, Peru, Bolivia and Argentina.


Seasonally dry, montane, rupestral habitats in inter-Andean valleys.


The name Arquita derives from the vernacular name of Arquita trichocarpa in Argentina ( Ulibarri 1996).


A revision of Arquita with a complete key to species is available in Gagnon et al. (Taxon 64(3): 468-490, 2015).


Burkart (1936); Ulibarri (1996); Lewis (1998: 167-171, 174-179); Lewis et al. (2010); Gagnon et al. (2015: 468-490).