The families of flowering plants
~ Xanthorrheaceae-Xanthorrhoeoideae of APG III
Excluding Asphodelaceae, Calectasiaceae, Dasypogonaceae, Hemerocallidaceae
Habit and leaf form. Shrubs, or arborescent (the habit characteristic, the trunk up to 2 m, or almost acaulescent); resinous. With a basal aggregation of leaves (when acaulescent), or with terminal aggregations of leaves; rhizomatous, or tuberous. Self supporting. Pachycaul. Xerophytic. Leaves evergreen; small to very large; alternate; spiral; leathery; sessile; sheathing (initially), or non-sheathing (subsequently). Leaf sheaths not tubular; with free margins. Leaves simple. Lamina entire; linear; parallel-veined; without cross-venules.
Leaf anatomy. Stomata present; paracytic.
Lamina with secretory cavities. Secretory cavities containing resin. The mesophyll containing calcium oxalate crystals. The mesophyll crystals solitary-prismatic. Minor leaf veins without phloem transfer cells (1 genus). Vessels present; end-walls scalariform.
Stem anatomy. Secretory cavities present; with resin (yellow, red and brown). Primary vascular tissue in scattered bundles. Secondary thickening anomalous; from a single cambial ring. Xylem with vessels, or without vessels. Vessel end-walls scalariform.
Root anatomy. Root xylem with vessels; vessel end-walls simple.
Reproductive type, pollination. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the gynoecium (from septal nectaries).
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences. Inflorescences scapiflorous; terminal; complex, dense, spikelike, multiflorous, pedunculate. Flowers bracteate; bracteolate; small; regular; 3 merous; cyclic; pentacyclic. Perigone tube absent. Hypogynous disk absent.
Perianth of tepals; 6; free; 2 whorled; isomerous; sepaloid (or bractlike); different in the two whorls (the outer members stiffer and shorter).
Androecium 6. Androecial members free of the perianth; all equal; free of one another; 2 whorled. Androecium exclusively of fertile stamens. Stamens 6; diplostemonous. Anthers dorsifixed; dehiscing via longitudinal slits; introrse. The endothecial thickenings spiral. Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; sulcate.
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. Stylar canal present. Stigmas 1; trilobate, capitate or punctiform. Placentation axile. Ovules 3–8 per locule (a few); horizontal, or ascending; non-arillate; anatropous; bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type.
Fruit non-fleshy; dehiscent; a capsule (woody or cartilaginous). Capsules loculicidal. Fruit 3–6 seeded. Seeds endospermic. Endosperm oily. Cotyledons 1. Embryo straight, or curved (situated transversely). Testa encrusted with phytomelan; black.
Seedling. Seedling collar not conspicuous. Cotyledon hyperphyll elongated; more or less circular in t.s. Coleoptile absent. First leaf dorsiventral. Primary root ephemeral.
Physiology, biochemistry. Not cyanogenic. Arthroquinones detected; polyacetate derived. Proanthocyanidins present (a trace only, in one of the two species screened), or absent; cyanidin. Flavonols present; kaempferol and quercetin. Ellagic acid absent.
Geography, cytology. Australian. Temperate to tropical. Australia. X = 22.
Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Asparagales. APG 3 core angiosperms; Superorder Lilianae; non-commelinid Monocot; Order Asparagales.
Species 66. Genera 1; only genus, Xanthorrhoea.
Illustrations. • Xanthorrhoea: habit and flower (Chittenden).
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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).
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 19th December 2012. http://delta-intkey.com’.