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The families of flowering plants

L. Watson and M.J. Dallwitz

Xeronemataceae M.W. Chase, Rudall & M.F. Fay

~ Asphodelaceae, Phormiaceae, Hemerocallidaceae

Habit and leaf form. Shrublike herbs. Perennial; with a basal aggregation of leaves (borne in fans); about 0.5–1.3 m high; rhizomatous (and stemless). Xerophytic. Leaves large to very large; alternate; distichous; flat; leathery and fleshy (the bases fleshy); sessile; strongly sheathing (with a distinct sinus between sheath and blade). Leaf sheaths with free margins. Leaves borne edgewise to the stem (broadly ensiform, equitant and isobilaterally flattened); simple. Lamina entire; lanceolate; parallel-veined; without cross-venules. Leaf development ‘graminaceous’.

Leaf anatomy. The leaf lamina bifacial. Stomata present; on both surfaces. The mesophyll containing crystals. The crystals raphides (these abundant, but no styloids).

Axial (stem, wood) anatomy. The axial xylem with vessels.

Root anatomy. Root xylem with vessels.

Reproductive type, pollination. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the gynoecium (via highly branched septal nectaries, which extend from the base of the ovary to openings around the base of the style). Pollination entomophilous, or ornithophilous (?).

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes (congested). The ultimate inflorescence units racemose. Inflorescences scapiflorous (the scape with sheathing bracts subtending the horizontal racemes well above the leaves); terminal; “dense, brushlike spikes”. Flowers bracteate; ebracteolate; medium-sized; regular; 3 merous; cyclic; pentacyclic. Perigone tube absent. Hypogynous disk absent.

Perianth of ‘tepals’ (these about 2 cm long); 6; free; 2 whorled (3+3); isomerous; petaloid; similar in the two whorls; red (along with all the inflorescence components). Tepal apex trichomes (TAT) absent.

Androecium 6. Androecial members free of the perianth; more or less all equal; free of one another; 2 whorled (3+3). Stamens 6; diplostemonous; alterniperianthial. Anthers dorsifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate. Microsporogenesis probably simultaneous. Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; mostly 1 aperturate; mainly mono- sulcate (with a few trichotomosulcate grains); scabrous, or muricate.

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 3 locular. Gynoecium stylate. Styles 1; attenuate from the ovary; apical (becoming twisted at maturity); much longer than the ovary. Stigmas 1. Placentation axile. Ovules 3–10 per locule (“several”); non-arillate; hemianatropous, or anatropous (?); bitegmic; crassinucellate. Embryogeny caryophyllad.

Fruit non-fleshy; dehiscent; a capsule (purplish). Capsules loculicidal. Dispersal unit the seed. Fruit many. Seeds endospermic; small to medium sized (about 5 mm long); wingless. Embryo well differentiated. Cotyledons 1. Testa with spines, or with tubercles; encrusted with phytomelan; black.

Seedling. Primary root persistent.

Physiology, phytochemistry. C3, or CAM (?).

Geography, cytology. Paleotropical and Antarctic. Frigid zone and tropical. Restricted to New Zealand (X. callistemon) and New Caledonia (X. moorei). 2n=36 (X. moorei) and 72 (X. callistemon).

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

Species 3. Genera 1; Xeronema.

General remarks. See Moore (1957); Clifford et al. in Kubitzki (1998); Chase et al (2000).

Illustrations. • Xeronema moorei: Bot. Mag. 136 (1910).

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.’.