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Primulaceae


This large family is most common in temperate regions of the Northern Hemisphere. Only a few native and introduced species occur in southern Australia, principally in open areas including disturbed roadsides and paddocks. One species of Samolus is a salt-marsh plant.

Characteristic features of the family Primulaceae in Australia include:

  • annual or perennial herbs with alternate, opposite or rosetted leaves which are simple, usually entire and sometimes gland-dotted
  • flowers white, yellow, red or blue with 5 virtually free petals and sepals and 5 stamens
  • ovary superior or half-inferior, with an unbranched style, and a single locule and ovules attached to a free-central placental column
  • fruit a capsule, dehiscing either longitudinally, by terminal valves, transversely around its equator, or irregularly

Description

Annual or perennial terrestrial herbs. Perennating by corms, tubers, rhizomes or crowns. Vegetative reproduction absent, or by rhizomes. Stem internodes terete, or distinctly angular. Internal secretions not obvious. Plants glabrous, or with simple, glandular or non-glandular, uniseriate hairs. Leaves alternate and spiral, opposite, or in whorls of 3 or 4, cauline or rarely basal or basal and cauline, petiolate, subsessile or sessile. Stipules absent. Lamina simple, symmetric, filiform, acicular, subulate, linear, lanceolate, ovate, elliptic, oblanceolate, obovate or spathulate; base cuneate, attenuate, rounded or cordate; margins entire, ±flat; one-veined, or the venation pinnate, with the midrib conspicuous or inconspicuous, and the tertiary venation reticulate or not; surfaces not punctate; herbaceous. All the flowers bisexual. Inflorescences terminal or axillary, consisting of panicles or solitary flowers. Bracts absent. Bracteoles present. Pollination by insects. Flowers odourless, stalked. Free hypanthium absent or ±present. Perianth regular, of 2 dissimilar whorls, imbricate in bud. Calyx segments free or fused, with (4–) 5 sepals or lobes; calyx cup-shaped, bell-shaped or tubular, herbaceous. Corolla segments fused or rarely free, with (4–) 5 lobes or petals, alternating with the calyx segments; corolla wheel-shaped, white, cream, yellow, orange, pink, red or blue, without contrasting markings, or streaked, spotted, etc, membranous; claws absent; lobes ±entire. Fertile stamens (4–) 5, alternating with the sepals or calyx lobes, at least partly fused to the corolla, free of the ovary and style, distinct from each other, all ±equal. Staminodes present or absent. Anthers dorsifixed or basifixed, versatile or not versatile, opening inwards by longitudinal slits, 2-celled; appendages absent or apical. Ovary superior and sessile, or part-inferior. Carpels 5, fused; ovary with 1 locule. Style terminal, single and unbranched, with the stigma clavate or truncate. Ovules numerous, sessile; placentation free-central. Fruit a dry capsule with irregular, circumscissile, denticidal or septicidal dehiscence; the perianth on the maturing fruit deciduous or dry and persistent. Disseminule macro-surface featureless or costate; micro-surface ±papillate, tuberculate or reticulate, orange, red, brown, grey or black, glossy or dull. Seeds numerous 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 Primulaceae has not yet been published in the Flora of Australia. It will appear in Volume 10.

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

† = some species native, others introduced
* = all species introduced

*Anagallis
*Asterolinon
†Lysimachia
Samolus


Anagallis arvensis (flowers)
Photo: K.Thiele © ABRS 


Anagallis arvensis (flowers)
Photo: L.Adams © L.Adams 


Samolus repens (flowers)
Photo: M.Fagg © M.Fagg