Systematics of Ledebouria sect. Resnova (Hyacinthaceae: Scilloideae: Massonieae), with a new subtribal classification of Massonieae

Abstract

The species in Ledebouria sect. Resnova are revised, with an identification key, full nomenclature, descriptions, ecological notes, and illustrations. Sect. Resnova is defined by its deeply campanulate flowers with tepals shortly connate basally and erect throughout or spreading distally; biseriate stamens with white, filiform filaments; sessile or subsessile ovary; and diagnostic seeds, obliquely obovoid with an inflated and invaginated raphe, and a finely puberulous-echinulate testa. Five species are recognised, divided between the monotypic ser. Lachenalioides, diagnosed by larger flowers with multi-nerved tepals, and ser. Resnova, with smaller flowers and uni-nerved tepals. Species in ser. Resnova are distinguished primarily by the presence or absence of hairs on one or both surfaces of the leaves, and by the presence or absence of a pseudopetiole. The new species Ledebouria hardyi J.C.Manning is described for a collection of plants from near Burgersfort in Limpopo with mostly solitary, markedly pseudopetiolate foliage. The species in sect. Resnova are geographically and ecologically separated by altitude and climate. A revised subtribal classification is provided for Massonieae, based on available phylogenetic hypotheses. Three subtribes are recognised: the monotypic Merwillineae is described for the genus Merwilla and is diagnosed by its white ovary and beige seeds; the genus Schizocarphus is transferred to join Ledebouria in Ledebouriinae, which is weakly diagnosed by the development of multiple inflorescences in some species and a flexuous scape; and Lachenaliinae is included within Massoniinae, which comprises all remaining genera in the tribe and is diagnosed by its few to many subglobose seeds per locule and often tunicated bulbs. This classification replaces existing hypotheses, which are inconsistent with available morphological and phylogenetic data.