Two new species of Gladiolus (Iridaceae: Ixioideae) from South Africa and notes on long-proboscid fly pollination in the genus

Abstract

Gladiolus rhodanthus is a new species known from a single population on the summit of the Stettynsberg near Villiersdorp in Western Cape, South Africa. The species most closely resembles G. hirsutus and G. caryophyllaceus but differs from both in flower shape and markings and in its ecology and reproductive biology. It forms part of a guild of long-tubed, pink-flowered species including Erica praecox, Pelargonium radiatum and Watsonia paucifolia which are pollinated by an undescribed long-proboscid fly, Moegistorhynchus sp. nov. (Diptera: Nemestrinidae). Gladiolus sekukuniensis is a new species known from three populations south of the Strydpoortberge in Northern Province. It closely resembles G. permeabilis subsp. edulis in vegetative features and in flower form, but differs from it in flower colour and in the elongate perianth tube. These floral features are apparently adaptations to pollination by long-proboscid flies.