The taxonomic arrangement within subfamily Ornithogaloideae (Hyacinthaceae) has been a matter of controversy in recent decades: several new taxonomic treatments have been proposed, based exclusively on plastid DNA sequences, and these have resulted in classifications which are to a great extent contradictory. Some authors have recognized only a single genus Ornithogalum for the whole subfamily, including 250-300 species of variable morphology, whereas others have recognized many genera. In the latter case, the genera are inevitably much smaller and they are better defined morphologically. However, some are not monophyletic as circumscribed. Phylogenetic analyses of Ornithogaloideae were based on nucleotide sequences of four plastid regions (trnL intron, trnL-F spacer, rbcL and matK) and a nuclear region (ITS). Eighty species covering all relevant taxonomic groups previously recognized in the subfamily were sampled. Parsimony and Bayesian analyses were performed. The molecular data were compared with a matrix of 34 morphological characters. Combinations of plastid and nuclear data yielded phylogenetic trees which are better resolved than those obtained with any plastid region alone or plastid regions in combination. Three main clades are found, corresponding to the previously recognized tribes Albuceae, Dipcadieae and Ornithogaleae. In these, up to 19 clades are described which are definable by morphology and biogeography. These mostly correspond to previously described taxa, though some need recircumscription. Morphological characters are assessed for their diagnostic value for taxonomy in the subfamily. On the basis of the phylogenetic analyses, 19 monophyletic genera are accepted within Ornithogaloideae: Albuca, Avonsera, Battandiera, Cathissa, Coilonox, Dipcadi, Eliokarmos, Elsiea, Ethesia, Galtonia, Honorius, Loncomelos, Melomphis, Neopatersonia, Nicipe, Ornithogalum, Pseudogaltonia, Stellarioides and Trimelopter. Each of these has a particular syndrome of morphological characters. As a result, 105 new combinations are made and two new names are proposed to accommodate the taxa studied in the new arrangement. A short morphological diagnosis, synonymy, details of distribution and an identification key are presented.

Iris L. s.l. is one of the most diverse and well-known genera in the Asparagales, with approximately 250–300 circumscribed species and significant economic impact. The taxonomy of the genus has suffered dramatic changes in the last century, particularly in the last decades after the application of molecular techniques. As a result several contrasting systematic arrangements are currently available to taxonomists. Many genera that were split from Iris s.str. in the past, on the basis of morphology (e.g., Hermodactylus, Iridodictyum, Juno, Pardanthopsis, and Xiphion, among others), are now a priori re-included in a very widely circumscribed Iris s.l. (incl. Belamcanda). This resulted in a more heterogeneous genus that is more difficult to define on morphological grounds. Testing congruence between taxonomic treatments and the results of recent molecular studies of Iris has never been performed, mostly due to the lack of proper taxonomic context. We generated several conventional phylogenies for Iris & outgroups using extensive sampling of taxa (187) and characters (10 plastid loci). We demonstrate that the natural history of Iris, written either as conventional molecular phylogenies or, if viewing in the context of the comparative approach, as a nested most parsimonious hierarchy of patterns, appear to be fully congruent with the narrow taxonomical treatment of the genus, restricted to the rhizomatous “bearded” taxa. The resulting topologies place Belamcanda, Pardanthopsis, and Gattenhofia as sisters to Iris s.str. and genus Siphonostylis as sister to Iris s.l. The present study clearly justifies the splitting of Iris s.l. into at least 23 genera, 18 of which have already been accepted in the past by numerous authorities. These genera are characterized by unique combinations of partly overlapping morphological characters and biogeography. Moreover, nearly the same entities, which we here recognize at a generic rank, were for centuries frequently referred to by horticulturists as “working-name” groups.

When treated in a broad sense, Iris (the ‘rainbow-flowers’) is one of the most diverse and well-known genera in the Asparagales. However, recent conventional phylogenetic and three-taxon statement re-treatments of the molecular data (cpDNA) for the irises (‘Iris sensu latissimo’ clade) showed that the obtained patterns of relationships appeared to be fully congruent to the narrow taxonomical arrangement of Iris (sensu stricto) to include only the bearded irises. Given this, we propose a new taxonomic arrangement of the rainbow-flowers with at least 25 previously recognised infrageneric taxa here accepted at the generic rank, of which 19 have already been treated as separate genera by different authors in the past. Morphological, phytochemical, karyological, distributional and molecular data are discussed which support the newly proposed system. Five genera and one section are described as new, 1 genus is amended, and 114 new nomenclatural combinations (2 genera, 3 sections, 1 series, 86 species, 14 varieties and 8 nothospecies) are established to accommodate the accepted names to the new generic system. Morphological descriptions and nomenclatural types are reported for each accepted genus, with types of four genera being designated here for the first time. Tentative distribution maps of relevant taxa, and illustrations of the most reliable morphological characters are included for the accepted genera. Principal synonyms and publication details are shown, and accepted infrageneric taxa are only referred to when previous information is not available. A key is also reported for genera identification. Our proposal mostly accords with the traditional distinction of groups currently in use by horticulturists, and it is favoured against an alternative treatment of an expanded Iris which renders a highly heterogeneous genus.

As a part of a taxonomic revision of the Iberian taxa of Ornithogalum, results corresponding to O. subgen. Cathissa are reported. Quantitative and qualitative characters are studied in detail, and they are evaluated for the taxonomic value of morphological characters of the three considered taxa: O. concinnum, O. broteroi, and O. reverchonii. A complete description is presented for all accepted species, and data on their biology, habitat, and distribution are also included. Moreover, a key is provided to facilitate identification.