Two new subspecies of Dietes (Iridaceae: Iridoideae), Dietes iridioides subsp. angolensis from Angola and Dietes bicolor subsp. armeniaca from eastern South Africa, with notes and range extensions for Dietes butcheriana and Dietes iridioides

Abstract

Background: Recent collections of Dietes have extended the known geographical range and morphological variation in several species.

Objectives: To describe additional taxa in Dietes to reflect the morphological and geographical variation in the species more accurately and to record significant range extensions. Method: Recent collections were compared with existing herbarium material and published literature.

Results: Two new subspecies in Dietes are described, viz. Dietes iridioides subsp. angolensis from Angola, constituting the first record of the species from that country, and Dietes bicolor subsp. armeniaca from eastern South Africa, which represents a range extension into southern KwaZulu-Natal. We also document a range extension for the local endemic Dietes butcheriana from KwaZulu-Natal into the Eastern Cape and discuss an anomalous population of D. iridioides, with long-lived flowers, from near Hankey in the Eastern Cape.

Conclusions: The range extensions and new infraspecific taxa increase our understanding of the diversity of Dietes in southern and south tropical Africa.