About the World Flora Online project

Scilloideae: Formerly circumscribed as Hyacinthaceae, this subfamily harbors a diverse group of geophytes being specially diverse in Mediterranean regions, widely distributed from Europe and North Africa to Central Asia and South America, renowned for their seasonality, bulbous habit, and iconic role in the spring floras of arid and seasonally arid regions.

Scilloideae, a subfamily of Asparagaceae, comprises around 60+ genera and approximately over 1000 species, primarily distributed in Africa and Eurasia. The group is well known for its geophytic life strategy, characterized by the presence of bulbs as underground storage organ. Plants have one or more basal leaves, forming a rosette, and a racemose inflorescence, and a basic floral plan of six more or less undifferentiated tepals. Many members are adapted to seasonally dry climates and exhibit striking floral diversity with only minimal morphological alteration from the basic plan of the flowers. The subfamily includes well-known genera such as Hyacinthus, Lachenalia and Ornithogalum, among several others.

Historically, the taxa now placed in Scilloideae were previously classified within the broadly defined Liliaceae and later in the segregate family Hyacinthaceae, depending on the system used. Molecular phylogenetic studies have demonstrated the close relationship of Hyacinthaceae with a diverse range of groups, now circumscribed in a broadly defined Asparagaceae, but separate from the Liliaceae.

Today, Scilloideae is divided into multiple tribes and subtribes based on molecular and morphological characteristics. The most widely accepted classification recognizes four tribes: Hyacintheae, Ornithogaleae, Oziroëeae, and Urgineeae (Chase et al., 2009). There are only a few characters to distinguish the tribes, the most consistent being the presence of particular groups of compounds which has led to research on the possible medical uses of plants in the subfamily.

Hyacintheae is the largest tribe and is further subdivided in three subtribes (Hyacinthinae, Massoniinae & Pseudoprosperinae), including around 30 genera and several hundred species. It is predominantly distributed in the Mediterranean Basin and southern Africa. Members of this tribe typically have blue, star-like flowers, that in some genera become connate (tubular) and have a wide range of colours. The tribe includes some highly ornamental and well known examples, such as Hyacinthus, Muscari, and Scilla. 

Ornithogaleae includes genera such as Ornithogalum, Galtonia, Albuca and Dipcadi, with a distribution extending from Africa to Europe and Asia. Members of this tribe typically have white, star-like flowers and a wide range of ecological adaptations. Some species are used in horticulture, while others have medicinal properties.

Oziroëeae is a small tribe that occurs in southern South America, representing an interesting biogeographical disjunction from other Scilloideae tribes, that is further reflected in its phylogenetic position as sister to the remaining tribes. It includes a single genus, Oziroë, which differs from other members of the subfamily in several morphological traits, such as bulb structure and floral arrangement.

Urgineeae include around 200 species distributed across Africa, Europe, and southwestern Asia. Its classification has been debated, with some treatments recognizing multiple genera (e.g., Austronea, Drimia, Indurgia, Schizobasis, Tenicroa, Thuranthos, Urginea, Urgineopsis, Vera-duthiea), while others favour a broader concept lumping many species into Drimia sensu lato. Recent phylogenetic studies, however, support a more fine-scaled classification (Martínez‐​Azorín et al., 2023).

Despite significant advances in the phylogenetic classification of Scilloideae, some issues remain unresolved. The placement of certain genera, particularly those with intermediate morphological characteristics, continues to be debated. Additionally, hybridization and polyploidy complicate genetic studies, leading to difficulties in defining species boundaries. Ongoing research by this group using genomic approaches will help clarify these issues and provide a more stable classification, which will be reflected in our here proposed taxonomic treatment of the group.

Key Contributors (in alphabetical order)

Böhnert, Tim (University of Bonn, Germany)

Crespo, Manuel B. (Universidad de Alicante, Spain)

Crouch, Neil R. (BRAM, South African National Biodiversity Institute, South Africa)

Culham, Alastair (University of Reading, UK)

David, John (University of Reading, UK)

Dold, Anthony P. (Rhodes University, South Africa)

Duncan, Graham (South African National Biodiversity Institute, Kirstenbosch National Botanical Garden, South Africa)

Eker, İsmail (Bolu Abant İzzet Baysal University, Türkiye)

Hankey, Andrew (South African National Biodiversity Institute, Walter Sisulu National Botanical Garden, South Africa)

Lekhak, Manoj M. (Shivaji University, India)

Martínez-Azorín, Mario (Universidad de Alicante, Spain)

Pinter, Michael (University Graz, Austria)

Yildirim, Hasan (Ege University, Türkiye)

Zarre, Shahin (University of Tehran, Iran)