: 164 The Plant Formations. 
Leaving out of consideration the climax-associations (tussock-steppe, heath, 
korekt or. scrub), the other river-bed associations contain about 56 species, ı of 
which is a low tree, 20 are shrubs, ı a liane, 25 herbs or suffruticose plants, 
8 of the grass-form, ı of the rush-form and ı fern. 
The principal growth-forms are: — mat-forming plants, often cireulanl 
prostrate creeping and rooting herbs; low shrubs often with leafless, green 
stems, and ericoid-shrubs. ae mad lutescens and Scleranthus biflorus are 
ale 
b. Unstable Biere sion Radeln association). 
Close to the streams, flooding of the surface is too common an occurrence 
to allow any plant to become established, but where submersion is rare, Raoulia 
tenuicaulis and Epilobium pedunculare, thanks to their abundant wind-borne 
seeds, quickly gain a footing. Both have creeping, rooting stems-which hug 
the ground. AR. tenuicaulis grows rapidiy owing to its mesophytic juvenile- a 
 reversion-shoots; it forms circular, flat, green and silvery patches, 60 cm, or 
much more, in Tara er XXX, Se 40). A few plants of Raoulia australis 
> may. also‘ be dee ; 
; ce. Stable river-bed. ; 
The Eee varies onsigerabiy aa as its surface is Shane or 
ilty, ‚ the : ‚flen; DR with a ‚dark een may be er as. Ba 
a en . Eastern tiver-bed. 
Hr rk a 
4 like Mens ot of. ei = 27 of. similar habit, ee 
| than R. Untescens, will be abundant. both 
EN ® 
