Donatiaceae

This is a family with only two species, one in southern South America, the other in Tasmania and New Zealand in alpine herbfields.

Characteristic features of the family Donatiaceae in Australia include:

• cushion-plant with small, close-packed linear leaves
  
• flowers solitary, white, star-like, embedded in the cushion, with 5 fused sepals and 5 free petals
  
• stamens 2 or 3
  
• ovary inferior, surmounted by a nectary-disc and 2 or 3 free styles
  
• fruits dry, indehiscent, enclosed in the persistent perianth

Description

Perennial terrestrial herbs. Perennating by crowns. Vegetative reproduction by rhizomes or stolons. Internal secretions not obvious. Plants glabrous or with simple, non-glandular, uniseriate hairs. Leaves alternate and spiral, cauline, sessile. Stipules absent. Lamina simple, symmetric, filiform, acicular, subulate or linear; base truncate; margins entire, revolute or recurved; one-veined, with the midrib conspicuous or inconspicuous, and the tertiary venation not reticulate; surfaces not punctate; leathery. All the flowers bisexual. Inflorescences terminal, consisting of solitary flowers. Pollination by insects. Flowers sessile. Floral disc present; nectaries present on the disc. Perianth regular, of 2 dissimilar whorls. Calyx segments fused, with 5 lobes; calyx cup-shaped, herbaceous. Corolla segments free, with 5 petals, alternating with the calyx lobes, imbricate in bud, white, without contrasting markings, membranous; claws absent; lobes ±entire. Fertile stamens 2, alternating with the calyx lobes, free of the corolla, free of the ovary and style, distinct from each other, all ±equal. Anthers dorsifixed, not versatile, opening outwards by longitudinal slits, 2-celled, with apical appendages. Ovary inferior. Carpels 2, fused; ovary with 2 locules. Style terminal, branching from the base. Ovules 2–12 per locule, sessile; placentation axile. Fruit a dry 'indehiscent capsule' (carcerulus); the perianth on the maturing fruit ?deciduous or dry and persistent. Disseminule micro-surface ±smooth, brown, ?dull. Seeds 1–10 per fruit. Aril absent. Cotyledons 2. Embryo round or shapeless.
(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 Donatiaceae has not yet been published in the Flora of Australia. It will appear in Volume 34.

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

Donatia