Puccinellia (Poaceae) in Western Australia
WILLIAMS, A.R.
Two new native species, Puccinellia longior and P. vassica, have been identified from Western Australia. P. longior is restricted to the outer edges of salt lakes and salt-affected pasture land along the lower western margin of the southwest wheatbelt region in WA, and has also been collected from a saline wetland reserve in southeast South Australia. P. vassica is endemic to the outer edges of marine saltmarsh in reserved areas of the Leschenault Inlet near Bunbury. It was previously known from the nearby Vasse-Wonnerup saltmarsh near Busselton but is now extinct there because engineering works have reduced the marine influence in the estuary. It may be on the verge of extinction in the Leschenault Inlet also because (a) it lives on the outer edge of the high tide influence and is thus prone to weed invasion from non-saline areas, (b) its culms disintegrate almost entirely each year so it provides little resistance to competition, and (c) it has a low recruitment rate, with only a few scattered plants surviving at each site. The most common species is Puccinellia stricta, which occurs on the margins of salt lakes and salt-affected pastoral land throughout the southwest wheatbelt region, from Hutt River in the north to the Esperance region in the east. WA collections of this species differ from those elsewhere in southern Australasia, but in a continuous way that did not easily yield taxonomic distinction. The main source of variation is probably that the WA habitats all have to endure long summer drought each year. The agriculturally introduced Middle-Eastern species P. ciliata is well naturalized in saline lands in southwest WA, and a single collection of the introduced P. gigantea is recorded. Other introduced species appear to have not survived.
