286 Displacement and Replacement of Associations and Species. 
2. Displacement and replacement by idrantians shrub-associations. 
Leguminous shrubs. 
Ulex europaeus‘), Cytisus scoparius, Lupinus arboreus and, to a much - 
lesser degree, Cylisus candicans invade open formations replacing and displacing 
the primitive vegetation. The seeds germinate in the neighbourhood of the 
parent shrub, and, in the first instance, the invasion of a formation was from 
shrubs purposely planted. At the present time, there are vast impenetrable 
thickets of pure (usually) Ver and Cy#sus on stony river-bed, which 
when in blossom are a glorious spectacle; both species too are abundant on 
lowland and lower-montane steppe and fixed dune. At an altitude of 700 m, 
in the South Island, the above are no longer aggressive. x 
Lupinus arboreus’) is confined to dry sandy or stony stations forming 
close thickets, 1.8 m or more high, on fixed or semi-stable dunes; it also occurs 
to some extent on river-bed. 
KRosaceous shrubs. 
Rosa Eglanteria, R. canina°), Rubus fruticosus agg. and R. laciniatus 
form individually, in many localities, extensive thickets which differ from those 
of the Zeguminosae inasmuch as they owe their distribution to birds*) while 
climate restricts Rubus to wet and Rosa to dry areas. 
Rubus thicket is especially aggressive in forest-clearings. Though occurring 
abundantly in many places, it attains the greatest luxuriance in the Western, 
orth-western, Egmont-Wanganui and Chatham districts. 
Rosa thicket becomes readily established on low tussock-steppe, m | 
eventually a pure association. It is specially abundant in the North-eastern 
district, ascending to about goo m. In Central Otago it is common on old 
mining tailings and in gullies in company with Discaria and the Ikeauhueng 
. Sambucus niger. 
Australian shrubs. i 5 
Hakea acicularis °), Epacris purpurascens, E. en and E. pulchella 
form extensive colonies in gumland’s-heath, the first-named being wide-spread, 
but the three epacrids being confined to one locality. The Hakea spreads 
after Zepfospermum scoparium is isn and Bann E the other shrubs first Ba 
their Bern after are: ° 
BT, 
sn This was early on Introdackd as a hedge-plant and is still extensively used for that purpose. 
Where rarely cut, the hedge exceeds 3.6m in height and seed is shed in profusion. Burning 
has no eilect in eradicating the plants; seedlings also are produced in millions and RN with 
great ty. 
Er 2 This shrub was purposely planted, or RR on dunes, in the first eine, in order 0 
check drifting Se This it is unable to do, but it forbids all sand-movement on the Bun 
3) of ed oecurrence. Ss | 
4) Some forms of Rubus Fruticosus spresd ER . means. of natural May - 
5) Hakca a has also been ‚observed recently. j 
