NEW SPECIES OF ARISTEA (IRIDACEAE) FROM SOUTH-AFRICA AND NOTES ON THETAXONOMY AND POLLINATION BIOLOGY OF SECTION PSEUDARISTEA

Aristea teretifolia and A. cantharophila are new species from the wint er-rainfall region of southern Africa. Both belong in section Pseudari stea, one of eight sections of this genus of ca. 52 species of sub-Sah aran Africa and Madagascar. Aristea teretifolia has pink, mauve, or cr eam flowers, the inner tepals of which are longer than the outer and h ave a large dark blotch near the base, and stands out in the section i n its very narrow linear or sometimes terete leaves. Aristea cantharop hila has narrow, linear to sword-shaped leaves fairly typical of the s ection, and mauve or white flowers with subequal tepals, each of which has a zone of dark color near the base. In their long pedicels, oblon g-trigonous ovary, large and deeply fringed stigma lobes, and woody, e longate, tardily dehiscent capsules these new species conform closely to the characteristic features of section Pseudaristea. Field observat ion suggests that both species are adapted for pollination by monkey b eetles (Scarabidae: Rutelinae), which use the flowers of these and at least one other species of the section as sites for feeding and mating . The dark markings on the tepals appear to mimic beetles and presumab ly encourage visits by these insects.