The South Justralian Naturalist. 
61 
Juctive. Everyone with whom we came into contact did all they 
-could for our comfort. In particular our thanks are due to the 
Station Master, Air. Hentschke, Mr. and Mrs. Diener, of Finniss 
.and Mr. Henley, of Gilberts. 
II. PLANT ASSOCIATIONS OF THE FLOOD PLAIN 
OF FINNISS. 
By E. H. Ising. 
The flood plain is 200 acres in extent. The hills gradually 
disappear going eastwards from the railway line and from the 
ford, a mile from the line, the country opens out into a swamp, 
the lower parts of which are flooded every year. The higher 
ground is only inundated after big floods and has a number of 
red gums {E. rostrata) growing upon it accompanied by weeds of 
many kinds. 
The junction between this higher ground and the part period- 
ically flooded is very marked. In the lower ground the vegeta- 
tion occurs in bands, or patches and the following associations 
Avere noted; — 
1. The Samphire Formation. 
2. A Rush Formation. 
3. A Rush - Mimulus Association. 
4. Scirpus - Juncus Association. 
5. Crassula - Triglochin Association. 
6. Scirpus lacuster formation. 
1. Samphire Formation. 
On the edge of this formation the ground is bare and the 
first plants occurring are Spergularia margmata (No. 2211) and 
a few specimens of Mimulus repens (No. 2212) mixed with the 
couch grass {Cynodon dactylon) and barley grass {Hordeum sp.). 
In the damper ground the barley grass entirely disappears but 
the Mimidus increases and forms a veritable mat over the ground, 
as it reaches the samphire {Arthrocnemum halocnemoides, var. 
pergranulatum) (No. 2213) it is not so plentiful. This leads to 
the zone of the samphire which is in open formation in the centre 
of which there are no other species. The ground develops cracks 
several inches deep becoming very dry in the summer. Thus the 
soil conditions are very much against plant-life and it seems only 
such plants as the samphire, with its highly developed water- 
bearing stems, can grow here. However Mivmlus re pens again 
enters the formation, and Triglochin striata (No. 2214) also comes 
m here as the samphire disappears. This formation represents a 
zone of about 20 feet in width. 
