Iosanthus (Hyacinthaceae subfam. Urgineoideae), a new genus from Southern Africa to include Ornithogalum toxicarium and its removal from Ornithogaloideae

Abstract

In the framework of a taxonomic revision of subfamily Urgineoideae based on morphological and genetic data covering numerous samples from its whole range of distribution, we here describe a new genus from Southern Africa. Iosanthus gen. nov. includes Ornithogalum toxicarium, a highly toxic species originally placed in subfamily Ornithogaloideae. However, our morphological studies support its inclusion in subfamily Urgineoideae based on the small bracts with a slight curve or short spur abaxially, the withered perigone circumscissile below and forming an apical cap and widely winged seeds with loose testa, a treatment also supported by its isolated phylogenetic position within this subfamily that facilitates the description of the new genus. Moreover, we also show that the holotype collection of this species represents a mixed collection of O. toxicarium in flower and an Albuca sp. in fruit, and therefore a lectotype is selected to maintain the current concept of this species.

Keywords:

• Asparagaceae
• Ornithogalum
• Scilloideae
• taxonomy
• distribution

Acknowledgments

The curators of all cited herbaria are thanked for kindly providing material and information. This work was partly supported by Fundación Ramón Areces (Spain), and H2020 Research and Innovation Staff Exchange Programme of the European Commission, project 645636: ‘Insect-plant relationships: insights into biodiversity and new applications’ (FlyHigh). The South African National Biodiversity Institute (SANBI), and Erich Van Wyk and Lufuno Makwarela are thanked for their assistance providing digital images of Ornithogalum toxicarium collections at PRE and for permission to publish these images. The Department of Environment and Nature Conservation of Northern Cape Province (collecting and export permits numbers FLORA046/2010, FLORA047/2010, FLORA069/2011, FLORA070/2011, FLORA61/2/2015, FLORA61/2/2015, FLORA0057/2017, FLORA0058/2017) and CapeNature of Western Cape Province of South Africa (collecting and export permits numbers AAA008-00031-0028, 0027-AAA008-00699, 0028-AAA008-00203) provided permission to collect herbarium specimens to the first author. Coleen Mannheimer, Silke Rugheimer and Frances Chase are thanked for their invaluable help with field work in southern Namibia and Ministry of environment of Namibia is thanked for granting collecting permits (permit number 2192/2016).

Disclosure statement

No potential conflict of interest was reported by the authors.