| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Hemerocallidaceae R. Br.

~ Liliaceae-Hemerocallidae, Xanthorrhoeaceae-Hemerocallidoideae.

Excluding Phormiaceae.

Habit and leaf form. Lilylike, glabrous herbs. Perennial; with a basal aggregation of leaves; shortly rhizomatous (with fibrous roots), or rhizomatous and tuberous (with root tubers). Mesophytic. Leaves alternate; distichous; flat, or folded; sessile; sheathing. Leaf sheaths not tubular; with free margins. Leaves simple. Lamina entire; linear, or lanceolate; parallel-veined; without cross-venules (?). Lamina margins entire.

Leaf anatomy. The leaf lamina dorsiventral. Stomata present; anomocytic. The mesophyll containing crystals, or without crystals (?). The crystals druses (?). Foliar vessels absent.

Axial (stem, wood) anatomy. Secondary thickening absent. The axial xylem without vessels.

Root anatomy. Root xylem with vessels; vessel end-walls scalariform.

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the gynoecium (via septal nectaries).

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes. The ultimate inflorescence units cymose. Inflorescences scapiflorous (the scape bracteate); terminal; considered to represent one or two double helicoid cymes (Krause 1930). Flowers medium-sized to large (not delimited from the pedicel by a joint); somewhat irregular to very irregular; zygomorphic. The floral irregularity involving the androecium (the stamens upcurved), or involving the perianth and involving the androecium. Flowers 3 merous. Perigone tube present (campanulate or funnelshaped). Hypogynous disk absent.

Perianth of ‘tepals’; 6; joined; 2 whorled; isomerous; petaloid; similar in the two whorls; brick red, or yellow to orange (sometimes striped, but not variegated with a droplike pattern). Tepal apex trichomes (TAT) present (i.e., Hemerocallis).

Androecium 6. Androecial members adnate (to the perigone tube); markedly unequal; free of one another; 2 whorled. Androecium exclusively of fertile stamens. Stamens 6; diplostemonous; long filantherous. Anthers dorsifixed (epipeltate, often twisted); versatile; introrse. Microsporogenesis simultaneous. Tapetum glandular. Pollen grains aperturate; 1 aperturate, or 3 aperturate (?); sulcate (trichotomosulcate?); 2-celled.

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 3 locular; sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical; much longer than the ovary (slender, slightly upcurved). Stigmas 1; truncate, or capitate; wet type. Placentation axile. Ovules 30–50 per locule (‘many’); anatropous; tenuinucellate. Embryo-sac development Polygonum-type. Endosperm formation nuclear.

Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal (opening from the top). Fruit many seeded. Seeds endospermic; subglobose, prismatic or slightly elongate, not flat. Embryo well differentiated (about the same length as the endosperm). Cotyledons 1. Embryo achlorophyllous (1/1); straight. Testa smooth; encrusted with phytomelan; black.

Seedling. Hypocotyl internode present (short). Seedling collar not conspicuous. Cotyledon hyperphyll compact; non-assimilatory. Coleoptile absent. Seedling cataphylls absent. First leaf dorsiventral.

Physiology, phytochemistry. Anthraquinones detected; polyacetate derived. Saponins/sapogenins present (steroidal). Proanthocyanidins absent. Flavonols present; kaempferol and quercetin. Ellagic acid absent.

Geography, cytology. Holarctic. Temperate. Temperate Eurasia, especially Japan. X = 11, the chromosomes not dimorphic, by contrast with Hosta.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Asparagales. APG III core angiosperms; Superorder Lilianae; non-commelinid Monocot. APG IV Order Asparagales (as a synonym of Xanthorrhoeaceae).

Species 16. Genera 1; only genus with Phormiaceae excluded, Hemerocallis.

General remarks. Differing conspicuously from the sensu stricto version of Xanthorrhoeaceae (q.v.) in numerous habit and floral morphological characters, as well as in anatomy and embryology.

Illustrations. • Hemerocallis fulva var. aurantiaca: Addisonia 14 (1929). • Hemerocallis fulva: Bot. Mag. 2 (1788). • Hemerocallis dumortieri: Addisonia 14 (1929). • Hemerocallis thunbergii (Chittenden).

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: 8th June 2026. delta-intkey.com’.

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