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Saxifragaceae


This is a large family mostly found in cold and temperate regions of the Northern Hemisphere. Only one species, Eremosyne pectinata, is found in Australia, on sandplains in south-western Western Australia. Although included in the Saxifragaceae in the Flora of Australia (following the system of Cronquist), there is evidence that Eremosyne would be better placed in a family of its own.

Characteristic features of the family Saxifragaceae in Australia include:

  • small, annual or ephemeral herbs, much-branched from the base
  • leaves entire to pinnately lobed, some forming a basal rosette and others smaller and alternating on the flowering stems
  • flowers in terminal dichotomous cymes, small, regular, cream or white, with 5 free sepals, petals and stamens
  • ovary part-inferior (i.e. with about 1/3 below the insertion of the sepals), with 2 free styles, developing into a 2-valved capsule

Description

Annual terrestrial herbs. Internal secretions not obvious. Plants with simple, non-glandular, unicellular hairs. Leaves alternate and spiral, both basal and cauline, petiolate, subsessile or sessile. Stipules absent. Lamina simple, auriculate, symmetric or conspicuously asymmetric, pinnatifid, pinnatisect, palmatifid or palmatisect; lamina/lobes lanceolate, ovate, oblanceolate or obovate; base cuneate, attenuate, cordate, lobed or oblique; margins entire or serrate, ±flat; 1-veined, or venation parallel, with the midrib inconspicuous, and the tertiary venation not reticulate; surfaces not punctate; herbaceous. Usually all the flowers bisexual. Inflorescences terminal, consisting of dichasial cymes. Bracts present. Pollination by insects. Flowers stalked. Floral disc absent. Free hypanthium ±present. Perianth regular, of 2 dissimilar whorls. Calyx segments free, with 5 sepals, valvate in bud, herbaceous. Corolla segments free, with 5 petals, alternating with the sepals, imbricate in bud, white or pink, without contrasting markings, membranous; claws absent; lobes ±entire. Fertile stamens 5, opposite to the sepals, free of the corolla, free of the ovary and style, distinct from each other, all ±equal. Anthers dorsifixed, versatile, opening sideways by longitudinal slits, 2-celled. Ovary part-inferior. Carpels 2, fused; ovary with 2 locules. Style terminal, branching from the base. Ovules 1 per locule, stalked; placentation axile or apparently basal. Fruit a dry, dehiscent capsule with irregular, septicidal or loculicidal dehiscence, or a schizocarp forming 1-winged mericarps (samarium), or rarely a fleshy, indehiscent berry; the perianth on the maturing fruit deciduous, or dry and persistent. Disseminule micro-surface striate, yellow, orange or pink, glossy. Seeds 2 per fruit. Aril absent. Cotyledons 2. Embryo straight.
(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 Saxifragaceae has not yet been published in the Flora of Australia. It will appear in Volume 10.

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

Eremosyne


Eremosyne pectinata (flowers)
Photo: G.Keighery G.Keighery 


Eremosyne pectinata (habit)
Photo: G.Keighery G.Keighery