What is "periglossum"

'Periglossum ' is a genus of flowering plants in the family Apocynaceae, first described as a genus in 1844. It is native to southern Africa.

1. Periglossum angustifolium DC. - South Africa
2. Periglossum kassnerianum Schltr. - South Africa
3. Periglossum mackenii Harv. - South Africa
4. Periglossum macrum Decne. - South Africa
5. Periglossum mossambicense Schltr. - Mozambique