Annual forb to 35cm tall. Leaves opposite each other on the lower stems, alternating up the stems higher up, sometimes alternating up the stems throughout. Leaves 0.1-4cm long, 0.2-11mm wide, flat, usually hairy, the edges flat or wavy. Flowers blue to mauve, sometimes white or pink, tubular, with five lobes (sometimes 3 or 4), in open groups or sometimes solitary at the ends of the stems.
Differs from Wahlenbergia communis, Wahlenbergia gracilis, Wahlenbergia queenslandica, and Wahlenbergia tumidifructa in that the lower leaves are opposite each other, from Wahlenbergia fluminalis and Wahlenbergia littoricola in that the free lobes of the flower are less than twice as long as the tube, and from Wahlenbergia luteola and Wahlenbergia graniticola in that the free lobes of the flower are 5mm long or less.
Description in G.M. Cunningham, WE Mulham, PL Milthorpe and J H Leigh (1981 and later printings) Plants of Western New South Wales page 628
Line drawings of flowers and fruiting bodies of seven species of Wahlenbergia in this key (but not Wahlenbergia graniticola, Wahlenbergia luteola, or Wahlenbergia stricta ssp. alterna) in Flora of South Australia 4th edition, Handbooks Committee on behalf of the South Australian Government (1986), Volume 3, page 1382. Line drawing of plant page 1379, Fig 626A.