Euchiton

Taxonomic status:Accepted

Occurrence status:Present

Establishment means:Native

Annual or perennial herbs, often rosetted and/or stoloniferous, with eglandular cottony hairs. Leaves basal and cauline, alternate, sessile or pseudopetiolate, entire. Capitula c. campanulate, rarely narrowly ovoid, solitary or aggregated into a terminal cluster, sometimes with axillary clusters below. Involucral bracts in 2–5 series, increasing in length from outer to inner, lower part of bracts herbaceous, margins hyaline, intermediate area sometimes pigmented. Florets all tubular, the outer filiform, female, with 3- or 4-lobed corollas; inner florets bisexual, usually far fewer than female florets (except in Euchiton umbricola), with purplish, 5-lobed corollas, anthers shortly tailed. Style branches linear, apices truncate. Cypselas flattened-ellipsoid, 0.6–1.5 mm long, usually with numerous microscopic paired papillae, sometimes with short hairs; pappus hairs entire or shortly ciliate at base, falling singly, in small groups or as a unit.

About 22 species in Australia, New Zealand, New Guinea and South-east Asia.

The generic boundary of Euchiton requires further clarification. Recently the genus Argyrotegium was separated from Euchiton based on the non-stoloniferous growth habit, and the absence of proximal microscopic papillae on the epidermal cells of the cypselas. This has left Euchiton now defined mostly by the stoloniferous growth form and paired papillae on the epidermal cells of the cypselas i.e. proximal and distal microscopic papillae on each cypsela epidermal cell. However, E. sphaericus does not produce stolons and E. umbricola lacks paired papillae (Flann 2010). It is possible that some current Euchiton species are better placed in separate genera, allowing Euchiton to be defined by a single character. This is especially the case for E. umbricola, which is distinctive amongst Euchiton for having lacerate involucral bracts and a much higher number of bisexual florets.

Source: Walsh, N.G. (1999). Euchiton. In: Walsh, N.G.; Entwisle, T.J. (eds), Flora of Victoria Vol. 4, Cornaceae to Asteraceae. Inkata Press, Melbourne.
Updated by: Val Stajsic, 2018-02-01
 
References

Flann, C. (2010). Morphometric study of Euchiton (Gnaphalieae: Asteraceae), Australian Systematic Botany 23: 285-305.

 
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