FRUIT STRUCTURE OF THE SOUTHERN AFRICAN SPECIES OF APODYTES E MEYER EX ARN (ICACINACEAE)

Fruit development and structure of three southern African species of A podytes were examined by light and scanning electron microscopy. These are A. dimidiata E. Meyer ex Am. subsp. dimidiata and two undescribed species designated Apodytes sp. nov. A and B. Fruits are unilaterally developed drupes, ellipsoid and somewhat compressed laterally, with a large succulent appendage. Appendages of A. dimidiata and Apodytes sp . nov. A are predominantly led, whereas those of Apodytes sp. nov. B a re e a pale translucent green. In all three species the appendages tur n black in old fruit. The exocarp is uniseriate and develops solely fr om the outer epidermis of the ovary wall. The mesocarp is partly paren chymatous, with vascular bundles and cells containing druse crystals o f calcium oxalate, and partly lignified ( = stone). The uniseriate end ocarp s. str. develops from the inner epidermis of the ovary wall. In a sense the Fruit of Apodytes is a composite of parts comparable to a nut (alternatively an achene) and a fleshy drupe. The drupaceous part (fleshy appendage) is a derived structure which develops From the ster ile carpel of a reduced locule. We suggest that the fleshy appendage o riginates as an indicator of seed/fruit maturity, and to attract avian dispersers. Limited field observations support the idea that the red/ black appendages of A. dimidiata and Apodytes sp. nov. A also serve as an edible reward for birds. Dispersal of fruit of Apodytes sp. nov. B , with its rather inconspicuously coloured appendage, may be dependent on a specialized fruit/frugivore relationship.