Hererolandia E. Gagnon & G. P. Lewis, 2016

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 : 23

1. Hererolandia E. Gagnon & G. P. Lewis gen. nov. Figs 4 , 5A-D

Diagnosis.

Hererolandia most closely resembles Lophocarpinia , but differs in having scattered curved, deflexed prickles on shoots (vs. scattered straight, conical spines, as well as modified, short, lateral, spinescent branchlets), pinnate leaves with (4-) 5-7 (-9) pairs of leaflets, arranged in fascicles (vs. alternate, pinnate leaves with 2-3 pairs of leaflets), and leaflets elliptic to oblong-elliptic (vs. leaflets obovate or elliptic-orbicular). The most distinctive feature of Hererolandia is the thinly woody, laterally compressed, almost circular to strongly sickle-shaped, usually 1-seeded fruit, covered in robust trichomes up to 6 mm long (vs. a segmented, falcate, lomentaceous fruit, with 4 coarsely serrate wings, breaking up into 1-seeded units).

Type.

Hererolandia pearsonii (L. Bolus) E. Gagnon & G. P. Lewis ≡ Caesalpinia pearsonii L. Bolus

Description.

A multi-stemmed shrub to 2 m, but usually less than 1 m tall, armed with curved, deflexed, 7 mm long prickles scattered along the branches; bark white or brown; stems terete and slightly sinuous, with a fine silvery indumentum on the young twigs, older stems glabrescent. Stipules not seen. Leaves pinnate, 7-17 mm long, subsessile, borne in fascicles on short woody brachyblasts that are usually subtended by a pair of tiny (sometimes obscure) prickles; leaflets opposite, (4-) 5-7 (-9) pairs per pinna, eglandular, covered in a fine silvery pubescence, 5-6.5 × 2.5-3 mm, elliptic to oblong-elliptic, apex obtuse, with an acuminate tip, main vein prominent, secondary venation not visible. Inflorescence a short raceme of bisexual flowers, about 5 cm long, usually borne on brachyblasts, covered in a fine silvery pubescence, with prickles along the inflorescence rachis; bracts about 2-3 × 1.5 mm, ovate, apex acute, caducous. Flowers zygomorphic; calyx with a short hypanthium, and 5 free sepals, c. 3-5 mm long, finely white pubescent, with the lower sepal cucullate and covering the other 4 sepals in bud, all sepals caducous, but hypanthium persistent as a ring around the stipe of the fruit; petals 5, yellow, free, c. 6-9 mm long, obovate; stamens 10, free, up to 10 mm long, eglandular, pubescent on the lower half; ovary pubescent, stigma a fringed and slightly indented chamber. Fruit a thinly woody, laterally compressed, almost circular to strongly sickle-shaped pod, c. 2-2.3 × 1-1.5 cm, dehiscing along the sutures, finely pubescent and covered in robust trichomes up to 6 mm long, usually 1-seeded. Seeds laterally compressed, about 6-8 mm long.

Geographic distribution.

A monospecific genus endemic to Namibia, on the Great Escarpment.

Habitat.

Semi-desert and desert areas, on stony, sandy soils.

Etymology.

Semiarid Hereroland, a region of eastern Namibia, is the type locality of Hererolandia pearsonii . The Herero people who inhabit this region are nomadic cattle herders and it is they and their region that are honoured in the name proposed for this monospecific genus, endemic to this restricted area of Namibia.

References.

Bolus (1920); Roux (2003); Curtis and Mannheimer (2005: 227).

Figures

Figure 4. Hererolandia pearsonii (L. Bolus) E. Gagnon & G. P. Lewis. A foliage and inflorescences B stem armature detail C leaflet lower surface D calyx lobes outer surface E lower cucullate calyx lobe side view F median petal inner surface G median petal side view H upper lateral petal inner surface I lower lateral petal inner surface J stamens and part of gynoecium, with calyx lobes removed K anthers dorsal and ventral views L gynoecium M stigma detail, N fruit. A, C-M from Mueller 1006, B, N from Geiss et al. 5156. Drawn by Juliet Williamson.

Figure 5. Hererolandia pearsonii (L. Bolus) E. Gagnon & G. P. Lewis. A shrubby habit B inflorescence C branch showing prickles and leaves D fruits (A. A. Dreyer, Sesriem Canyon, Namibia, unvouchered). Haematoxylum brasiletto H. Karst. E mature fruit dehiscing along the mid-valve (C. E. Hughes, Mexico, unvouchered) F inflorescences and leaves (G. P. Lewis, Mexico, Lewis 2057 (K )) G distinctively fluted trunks (C. E. Hughes, Oaxaca, Mexico, Hughes 1947 (FHO )) Lophocarpinia aculeatifolia (Burkart) Burkart H shrub with flowers, armed with straight conical spines I fruits (R. H. Fortunato, Paraguay, Fortunato 8650 (BAB )).