Mesquite & Prosopis

Prosopis spp.

Description

Shrub or multi-stemmed tree, occasionally single-stemmed, with sturdy spines. Often confused with Acacia, but it has straight spines rather than thorns. Leaves twice-compound, with few pinnae pairs (1-2, sometimes 3). Flowers yellow, in fluffy spikes carried near branch tips. Fruit long, cylindrical or flattened pods with raised bumps over the seeds, often beaked.

Discussion

Widespread in Namibia, although often localised. Highly invasive in dry river beds, especially in the south-east, out-competing local trees and extremely water-hungry. The pods are nutritious fodder, while the wood burns well, and the sawdust is excellent for smoking fish and meat. These species produce masses of pollen in spring, to which many people are dangerously allergic. The City of Windhoek has a by-law that prohibits the planting of any of these species.

There are at least three species in Namibia, Prosopis glandulosa, P. velutina and P. chilensis, the most common of which is P. glandulosa. These species hybridise freely, so they may be difficult to identify (see table below). For this reason we will record them as a single species for the purpose of this atlas.

Prosopis glandulosa

Common name: Honey mesquite (English); ‡khòńhai.s (Khoekheogowab); |nàra.s (Damara); !khàa.s (Nama)

Origin: Southwestern United States and Mexico

Prosopis velutina

Common name: Velvet mesquite (English)

Origin: United States and Mexico

Prosopis chilensis

Common name: Chilean Prosopis (English)

Origin: South America

Characteristics of Prosopis glandulosa, P. velutina and P. chilensis

Prosopis species	Thorns	Foliage texture	Number of pinnae pairs	Pinnae length (cm)	Leaflet pairs per pinna	Leaflet length and width (mm)	Leaflet distance apart	Leaflet shape	Inflorescence length (cm)	Pod shape and colour when ripe	Pod length and width (cm)	Number of seeds per pod
glandulosa	1-4.5 cm long, sometimes single.	Smooth	1 or 2	6-17	6-17	20-63 x 1.5-4.5	Distant, 7-18mm apart	Linear or oblong	5-14 cm	Almost straight, sometimes slightly curved, Straw-yellow or tinged violet	8-20 x 0.7-1.3	5-18
velutina	1-2 cm long.	Finely hairy	1 or 2, sometimes 3	2-9	12-30	4-13 x 2.0-4.0	adjacent	obtuse	5-15 cm	Straight or slightly curved. Yellow, sometimes reddish	8-16 x 0.6-1.0	10-17
chilensis	Sometimes thornless, often with few thorns. Thorns conical, up to 6 cm long.	Smooth, rarely finely fringed	1 or 2, sometimes 3	8-24.5	10-29	11-54 x 1.1-3.0	Distant, 4-12mm apart	Long-linear	7-12 cm	Straight or curved, sometimes very curved. Straw-yellow	12-18 x 1.0-1.8	20-32