In Namibia prosopis is widespread. There are several types, including the honey prosopis, Prosopis glandulosa, and the velvet prosopis, P. velutina. The spines of P. glandulosa emerge at nodes on the branches and the leaflets of P. velutina have grey hairs. Prosopis trees started to spread in the southern African region after pods were imported in the 1940s as a source of cattle fodder. Livestock ate them and the indigestible seeds were then distributed in the veld. Due to the easy propagation of the seeds, prosopis trees established themselves easily. Wild and du Plessis point out that in one district in the Great Karoo, prosopis increased by 400% within 17 years. The result was an impenetrable stand of trees bearing no pods. This has led South Africa to proclaim it an invader species in terms of the Conservation of Agricultural Resources Act (Act No 43 of 1983).