F. Muell., Enum. Greg. Pl. 8 (1859).
Synonymy: Othonna gregorii
Common name: Fleshy groundsel.
Erect simple to much-branched glabrous annual herb, 20-40 cm high; leaves fleshy, broadly linear, 3-9 x 0.2-0.5 cm, entire, sessile.
Inflorescence of 1-3 capitula, solitary at the apices of axillary and terminal branches, peduncles 6-15 cm long, leafy, apically dilated and hollow; involucre ecalyculate, cylindrical, of 10-13 segments fused almost to their apices except for 1-3 partial slits which deepen as the ripening achenes expand laterally; ray florets 8-11 rarely 14; ligules 10-17 rarely 23 x 2-6 mm, 4-nerved; disk florets 40-55, sometimes fewer; style-arms terminated by a short bristle of more or less fused papillae.
Achenes cylindrical, those of the ray florets olive-green, 5-6 x 2-3 mm, those of the disk florets reddish and 7-10 x c. 2 mm, all densely pubescent with spreading hairs c. 1 mm long; pappus persistent, of stout barbellate or subplumose white bristles.
Cunningham et al. (1982) Plants of western New South Wales, p. 676.
A plant of central Australia, extending into mallee formations and coastal areas of low rainfall, most often in deep red sands of the interior among a wide variety of vegetation types, sometimes on clay soil near salt lakes and on and around clay pans, infrequently on stony ground. Germination dependent on rainfall, ultimate size attained dependent on subsequent moisture supply.
S.Aust.: NW, LE, NU, GT, FR, EA, EP, MU. W.Aust.; N.T.; Qld; N.S.W.; Vic.
Flowering time: July — Dec., occasional throughout the year.
SA Distribution Map based
on current data relating to
specimens held in the
State Herbarium of South Australia
Senecio gregorii, with its ecalyculate and largely connateinvolucre does not, as Bentham noted, fit well in Senecio. As Jeffrey (pers. comm.) points out, it shares these and other features, such as the distinctive achenial pubescence and epidermal cell type, solely with the mainly African othonoid group of genera. He proposes to publish an appropriate new combination.
Mueller originally described the achene as glabrous, but in Rep. Babbage Exped. 1858 he wrote: "Achenes in the Wonnomulla specimen white silky". It is not clear on what the original description of the achene was based, as Mueller's specimen (Gregory, Cooper River) at Melbourne shows no sign of the involucre having been opened.
Not yet available