Charles Austix Gardner. 
(f) HALOPHYTIC AND DUNE FORMATIONS. 
The halophytic formations will be dealt with at greater length imder the 
chapter on the Eremean Province, since these formations differ very slightly, 
if at all, within Western Australia, and are more typical of inland localities. 
The only distinctive lialophytic formations of the South-West Province are 
the salt marshes which fringe the estuaries, and the littoral marshes in proximity 
to the coast. These are fiats which are wet or inundated during the winter 
months, but completely dry in summer, except under unusual conditions. 
The most characteristic plants are those broadly classed as “ samphires,” 
belong to the genera Arihrocnemum and Pachycornia, halophytic succulents 
which also occur in the small saline depressions found constellated through 
the country, and which predominate in such localities. Other Chenopodia- 
ceae are Suaeda maritima, Samolus rej^tcns and S. Valerandi, Didymanthus 
Roei and Atriplex hypoleucay and certain grasses such as Puccinellia and Pholi- 
zirus. 
The dune plants possess little that is distinctively Australian. It is on the 
littoral dunes that we find so many palaeotropic groups and species which 
belong more distinctively to the Eremea. Amongst the former are Festuca 
and SpinifeXy CarpobrotuSy Atriplex cinerea, Pelargoniumy Nitraria Schoeberi, 
Cakile maritima (which is surely a natural immigrant), Arctotis nivea, a more 
recent immigrant, and certain Australian maritime dune species such as 
Lepidospemm gladiatum, Scirpus yiodositSy Scaevola crassifoliay and Acacia 
cylopis. It is interesting to find here, plants which more properly belong to the 
Eremea, such as Callitris, Exocarpus sparteOy Eremophila glabray Alyxia buxi- 
Jolia, and Santalum acuminatum. These are found in soils which are physically 
or physiologically dry, and the relationship of the maritime dune vegetation 
to the Eremea is most interesting, but on the other hand, especially under soil 
and temperature conditions, the strand vegetation cannot be taken as typical 
of the country w^hich it fringes. In the northern areas, that is, between the 
Hill and Murchison Rivers, there is an extensive development of a littoral 
formation of shrubs or small trees in which certain species of Acacia play an 
important part. To the north the area is rich in lianes, and although the 
shrubby plants are in close association, there is also a marked development 
of herbaceous species. Here again is a marked admixture of plants which we 
regard as being typically Eremean, e.g., GyrocarpuSy Zygophyllum, Jasminum, 
Hibiscus, and Cienfugosia, or tropical (Aphanopetalum and Dioscorea). 
(g) SAND HEATHS. 
Wherever the soil is of a sandy nature, whether a loose detritus or the 
more compacted yellow or red sand of the interior, lieath-like formations 
predominate. These heaths vary from typical low heath in the humus soils 
of the southern littoral, to the taller heaths of the sand of the savannah and 
sclerojjhyllous woodland zones and the northern littoral. The shrubs usually 
vwy from -5-] metre in height, and are often intermixed with small thickets 
of the mallee type of Eucalyptus, Melaleuca, or several Proteaceae, but their 
constitution varies considerably within the various climatic areas, those 
of the wet districts often merging into swam}) formations, while those of 
the interior and tlie north usually occupy only the high ground. The most 
extensive areas of this formation occur between the Hill and Greenough 
rivers, between the Hutt and Murchison rivers, between Tammin and Ben- 
dering, and in the southern littoral between King George’s Sound and 
Israelite Bay. In other j)laces the heath areas, intersected by thickets and 
woodland, form a broad |)attern in the broad zone lying between the 500 
and 175 mm. seasonal isohyets. 
