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Xanthorrhoeaceae


This family is almost entirely Australian (with a few species occurring in Papua New Guinea and New Caledonia). Members are usually found in open, dry places, often on sandy soils, in woodlands and heath from the coasts to the Central Australian ranges. The greatest diversity of genera is in the south-west of Western Australia.

Characteristic features of the family Xanthorrhoeaceae in Australia include:

  • tough, rush-like herbs to stout, small trees with branched or unbranched trunks and a crown of linear, tough leaves
  • flowers regular, creamy-white, yellow or blue, usually in dense clusters on a panicle or in dense erect spikes or knob-like heads, rarely (Calectasia) solitary
  • perianth of 6 free or united segments, sometimes rather thick and tough, and usually 6 stamens adjacent to the perianth segments
  • ovary superior, developing into a tough capsule (these sometimes more or less immersed in the stout fruiting spike), or a berry or hard nut

Description

Evergreen shrubs or perennial terrestrial herbs. Perennating by rhizomes or crowns. Vegetative reproduction absent, or by rhizomes. Stems unarmed, or rarely (by misinterpretation), with thorns or spines arising from the leaf axils. Internal secretions not obvious, or of resin. Plants glabrous, or with simple, non-glandular hairs. Leaves alternate and spiral, or distichous, or apparently whorled, or if herbs then the leaves cauline, all or mostly basal, or both basal and cauline, sessile. Stipule-like lobes absent. Lamina simple, symmetric, filiform, acicular, subulate or linear; margins entire, ±flat, involute or incurved; venation parallel, with the midrib conspicuous or inconspicuous, and the tertiary venation not reticulate; surfaces not punctate; herbaceous or leathery; distinctive odour absent or aromatic. Leaf ligule absent. Male and female flowers occurring on separate plants, or with all the flowers bisexual. Inflorescences terminal or axillary, consisting of capitula, spikes, racemes, panicles, cymes, umbels or solitary flowers. Bracts and bracteoles present. Pollination by insects or birds. Flowers odourless or fragrant, sessile or stalked. Perianth regular, of 2 dissimilar whorls or all whorls ±similar, imbricate in bud. Calyx segments free or fused, with 3 sepals or lobes; calyx bell-shaped or funnel-shaped, papery. Corolla segments free or fused, with 3 (or 6) petals or lobes, alternating with the sepals or calyx lobes; corolla bell-shaped, funnel-shaped or salver-shaped, white, yellow, magenta or purple, without contrasting markings, membranous; claws absent; lobes ±entire or with terminal appendage. Fertile stamens 6, opposite to and/or alternating with the sepals or calyx lobes, free or at least partly fused to the corolla, free of the ovary and style, distinct from each other or fused by their filaments into an open or closed tube, all ±equal. Anthers dorsifixed or basifixed, versatile or not versatile, opening inwards by pores or by longitudinal slits, 2-celled; appendages absent or apical. Ovary superior and sessile. Carpels 3, fused; ovary with 1 or 3 locules. Style terminal, single and unbranched, or branched above or from the base. Ovules 18 per locule, sessile; placentation axile. Fruit a dry, dehiscent loculicidal capsule, sometimes with explosive dehiscence, or an indehiscent nut; the perianth on the maturing fruit deciduous, or dry and persistent. Disseminule micro-surface ±reticulate or rugose, yellow, orange, red, brown or black, glossy or dull. Seeds 18 per fruit. Aril absent. Cotyledons 1. Embryo straight or curved.
(Note: this description has been generated from the coded data compiled for the key. Any errors in the key data will be reflected in the descriptions.)

A treatment of the family Xanthorrhoeaceae has been published in:
Flora of Australia 46: 88-171.

Australian genera of Xanthorrhoeaceae (as recognised for the Flora of Australia)

Acanthocarpus
Baxteria
Calectasia
Chamaexeros
Dasypogon
Kingia
Lomandra
Romnalda
Xanthorrhoea
Xerolirion


Acanthocarpus preissii (flowers)
Photo: M.Fagg M.Fagg 


Calectasia cyanea (flowers)
Photo: M.Fagg ANBG 


Chamaexeros fimbriata (flowers)
Photo: P.Ollerenshaw ANBG 


Dasypogon obliquifolius (flowers)
Photo: M.Fagg ANBG