Anne Harris and Andrew Brown
Interim Recovery Plan No: 158
Department of Conservation and Land Management, October 2003
- National Recovery Plan for the Whicher Range Dryandra (Dryandra Squarrosa subsp. Argillacea)(PDF - 147 KB) | (ZIP - 2502 KB)
The first known collection of Dryandra squarrosa subsp. argillacea, housed at the Western Australian Herbarium, was made in 1954 by R. Royce, near Busselton. A number of additional collections have since been made with a number of new populations located during the floristic survey of the Southern Swan Coastal Plain (Gibson et al. 1994). This survey identified the taxon as being mainly restricted to ironstone areas. These ironstone soils are highly restricted and extensively cleared and additional new populations are most likely to occur on small remnants of vegetation on private property. Currently, D. squarrosa subsp. argillacea is known from 11 populations consisting of around 4260 plants.
Dryandra squarrosa (R.Br.) subsp. argillacea A.S.George has 3 to 6 teeth on each side of the leaves, which are 5 to 9 mm wide. The individual flowers are 1.8 to 1.9 cm long on a 2 mm long hairless limb, and appear from June to November. The style is 2 to 2.5 cm long, and the pollen presenter is 0.8 to 1 mm long (Brown et al. 1998).
Dryandra squarrosa subsp. argillacea is distinguished from the species D. squarrosa subsp. squarrosa by its smaller perianth with a glabrous limb. The leaves are also usually smaller and more slender (George 1996).
Dryandra squarrosa subsp. argillacea occurs near Busselton on the Swan Coastal Plain. The taxon occurs in winter-wet clay over ironstone in open to tall shrubland (George 1996). Some of the populations however, are found in lateritic gravel pits and not on ironstone. It is possible that these populations may have been introduced to the sites through movement of seed contained in soil.