Asparagales

Asparagales (asparagoid lilies) are a diverse order of flowering plants in the monocots. Under the APG IV system of flowering plant classification, Asparagales are the largest order of monocots with 14 families, 1,122 genera, and about 36,000 species, with members as varied as asparaguses, orchids, yuccas, irises, onions, garlics, leeks, and other alliums, daffodils, snowdrops, amaryllis, agaves, butcher's broom, agapanthuses, Solomon's seal, hyacinths, bluebells, spider plants, grasstrees, aloes, freesias, gladioli and crocuses. Most species of Asparagales are herbaceous perennials, although some are climbers and some are trees or shrubs. The order also contains many geophytes (bulbs, corms, and various kinds of tuber). The leaves of almost all species form a tight rosette, either at the base of the plant or at the end of the stem, but occasionally along the stem. The flowers are not particularly distinctive, being 'lily type', with six tepals and up to six stamens. One of the defining characteristics (synapomorphies) of the order is the presence of phytomelanin, a black pigment present in the seed coat, creating a dark crust. Phytomelanin is found in most families of the Asparagales (although not in Orchidaceae, thought to be the sister-group of the rest of the order). The order Asparagales takes its name from the type family Asparagaceae and has only recently been recognized in classification systems. The order is clearly circumscribed on the basis of molecular phylogenetics, but it is difficult to define morphologically since its members are structurally diverse. The order was first put forward by Huber in 1977 and later taken up in the Dahlgren system of 1985 and then the Angiosperm Phylogeny Group systems. Before this, many of its families were assigned to the old order Liliales, which was redistributed over three orders, Liliales, Asparagales, and Dioscoreales, based on molecular phylogenetics. The boundaries of the...