The families of flowering plants
Habit and leaf form. Erect herbs. Plants green and photosynthesizing. Perennial; more or less with a basal aggregation of leaves; cormous (the corm bulb-shaped, tunicated, including more than one internode). Leaves alternate; spiral; flat; sessile; sheathing; simple. Lamina entire; linear, or lanceolate; parallel-veined; without cross-venules. Lamina margins entire. Leaf development probably graminaceous.
Leaf anatomy. Stomata present; anomocytic. The mesophyll containing crystals. The crystals raphides.
Axial (stem, wood) anatomy. Secondary thickening absent.
Reproductive type, pollination. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the gynoecium (?).
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in panicles. The ultimate inflorescence units cymose. Inflorescences scapiflorous to not scapiflorous (the scape leafy at least below); terminal; panicles with varying degrees of branching, often few-flowered, sometimes umbel-like. Flowers medium-sized; regular; 3 merous; cyclic; pentacyclic. Perigone tube absent.
Perianth of tepals; 6; free; 2 whorled; isomerous; petaloid; similar in the two whorls (but the outer members somewhat narrower); nearly white, or violet, or blue. Tepal apex trichomes (TAT) present (Ixiolirion).
Androecium 6. Androecial members adnate (to the bases of the tepals); free of one another. Androecium exclusively of fertile stamens. Stamens 6; diplostemonous; filantherous (the filaments long and slender). Anthers basifixed; non-versatile; dehiscing via longitudinal slits; latrorse to introrse; tetrasporangiate. Endothecium developing fibrous thickenings. The endothecial thickenings spiral. Microsporogenesis simultaneous. Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; sulcate; 2-celled.
Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; synstylovarious; inferior. Ovary 3 locular. Epigynous disk absent. Gynoecium stylate. Styles 1; apical; much longer than the ovary. Stigmas 3 (the style apically tribrachiate); dry type. Placentation axile. Ovules 15–50 per locule (rather numerous); ascending; anatropous; crassinucellate. Endosperm formation helobial.
Fruit non-fleshy; dehiscent; a capsule. Seeds endospermic. Embryo well differentiated (nearly as long as the endosperm). Cotyledons 1. Embryo straight (fusiform). Testa encrusted with phytomelan; black.
Physiology, phytochemistry. Alkaloids absent (by contrast with Amaryllidaceae).
Geography, cytology. Holarctic and Paleotropical. Southwest Asia. X = 12.
Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Asparagales. APG III core angiosperms; Superorder Lilianae; non-commelinid Monocot. APG IV Order Asparagales.
Species 1–4. Genera 1; only genus, Ixiolirion.
Illustrations. • Ixiolirion montanum: Bot. Reg. 30 (1845).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 5th March 2018. delta-intkey.com/angio’.