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The families of flowering plants

L. Watson and M.J. Dallwitz

Asparagaceae Juss.

~ Former Liliaceae, Asparagaceae-Asparagoideae of APG III.

Excluding Agavaceae, Aphyllanthaceae, Hesperocallidaceae, Hyacinthaceae, Laxmanniaceae, Ruscaceae, Themidaceae.

Habit and leaf form. Shrubs, or lianas, or herbs. Switch-plants; with the principal photosynthesizing function transferred to stems (as represented by axillary clusters of cladodes). Leaves much reduced (to small bractlike structures). The herbs perennial; without conspicuous aggregations of leaves; rhizomatous. Self supporting, or climbing; the climbers stem twiners; twining anticlockwise (Asparagus). Leaves alternate; membranous (scales); more or less sheathing; simple. Lamina entire; parallel-veined. Leaves exstipulate.

Leaf anatomy. The mesophyll commonly containing mucilage cells (with raphides); commonly containing crystals. The crystals raphides. Foliar vessels absent.

Axial (stem, wood) anatomy. Secondary thickening absent.

The vessel end-walls scalariform.

Root anatomy. Roots with velamen (often), or without velamen. Root xylem with vessels; vessel end-walls simple.

Reproductive type, pollination. Plants hermaphrodite, or monoecious, or dioecious, or polygamomonoecious. Female flowers with staminodes (i.e. with nonfunctional stamens). Floral nectaries present. Nectar secretion from the gynoecium (via septal nectaries).

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when aggregated, in cymes, or in racemes, or in umbels. The ultimate inflorescence units probably cymose. Inflorescences umbel-like or racemelike, but probably always determinate?. Flowers small; regular; 3 merous; cyclic. Perigone tube present, or absent. Hypogynous disk absent.

Perianth of ‘tepals’; 6; free, or joined; 2 whorled; isomerous; sepaloid, or petaloid; similar in the two whorls; green, or white, or yellow. Tepal apex trichomes (TAT) absent (Asparagus).

Androecium 6. Androecial members adnate (at the base of the perianth); free of one another; 2 whorled. Androecium exclusively of fertile stamens (in male and hermaphrodite flowers). Stamens 6; diplostemonous. Anthers dorsifixed, or basifixed; dehiscing via longitudinal slits; introrse. The endothecial thickenings spiral. Microsporogenesis successive. Pollen grains aperturate; 1 aperturate; sulcate; 2-celled.

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary 3 locular. Gynoecium stylate. Styles 1; apical; shorter than the ovary to about as long as the ovary (usually rather short). Stylar canal present. Stigmas wet type, or dry type. Placentation axile. Ovules 2–12 per locule; non-arillate; hemianatropous, or anatropous, or orthotropous; crassinucellate. Embryo-sac development Polygonum-type. Endosperm formation nuclear.

Fruit fleshy; indehiscent; a berry. Seeds endospermic. Endosperm oily. Embryo well differentiated. Cotyledons 1. Embryo achlorophyllous (1/1); straight, or curved. Testa encrusted with phytomelan, or without phytomelan (?); ‘often' black.

Seedling. Hypocotyl internode present (short). Seedling collar not conspicuous. Coleoptile absent. Seedling cataphylls present. Primary root persistent.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Asparagus. Anatomy non-C4 type (Asparagus). Not cyanogenic. Alkaloids absent. Arbutin absent. Saponins/sapogenins present (steroidal). Proanthocyanidins absent. Flavonols present, or absent; kaempferol, or kaempferol and quercetin. Ellagic acid absent. Sieve-tube plastids P-type; type II.

Geography, cytology. Holarctic, Paleotropical, Cape, and Australian. Temperate, sub-tropical, and tropical. Widespread, especially Old World.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Asparagales. APG III core angiosperms; Superorder Lilianae; non-commelinid Monocot. APG IV Order Asparagales (Asparagaceae-Asparagoideae).

Species about 370. Genera 1, or 3; Asparagus, Hemiphylacus(?), Myrsiphyllum, Protasparagus.

General remarks. The comparative data compiled for this package offer support for retaining Asparacaceae sensu stricto, Agavaceae, Aphylanthaceae and Hyacinthaceae as distinct taxonomic groups. If family names are still intended to convey widely useful information, it is inappropriate to merge them at this level.

Economic uses, etc. Cultivated ornamentals, and culinary asparagus (A. officinalis).

Illustrations. • Le Maout and Decaisne: Asparagus. • Asparagus officinalis (B. Ent., 1839). • Asparagus officinalis: Eng. Bot. 1515 (1869). • Asparagus umbellatus: Bot. Mag. 126 (1900).

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: 15th April 2018.’.