SOME MODIFIED ASSOCIATIONS. 149 
especially Yorkshire fog (Holcus lanatus) and sweet vernal (Anthox- 
anthum odoratum), have become common on many upland pastures, 
the seed from which such grasses originated having come in horse-feed, 
or been brought by the wind or the grazing-animals themselves, or 
even having been sown when grass-seed has been purposely scattered 
after a burn. Various unpalatable indigenous species have greatly 
increased on these upland pastures—e.g., certain turf-forming raoulias 
(Raoulia subsericea, R. glabra); the turfy coprosma (Coprosma Petrie), 
of similar habit; the common mountain-groundsel (Senecio belli- 
dioides) ; the false edelweiss (Helichrysum bellidioides) ; the swamp-lily 
(Chrysobactron Hookeri); the mountain-piripiri (Acaena Sanguisorbae 
var. pilosa); the spineless piripiri (A. wmermis); various gentians 
(Gentiana); and, perhaps most abundant of all, the small sharp- 
leaved heath (Leucopogon Frasert). 
The association of dune-hollows and even of the actual sandhills 
is considerably modified in many places by the establishment of white 
clover (Trifolium repens), suckling-clover (7. minus), haresfoot clover 
(T. arvense), the toothed medic (Medicago denticulata), the melilot 
(Melilotus arvensis), and the harestail-grass (Lagurus ovatus). 
Salt-meadow is not a likely association to be interfered with, but 
in some places it has been heavily invaded by the curved snaketail- 
grass (Lepturus incurvatus) or the buck’s-horn plantain (Plantago 
Coronopus), both European coastal plants. 
Where cattle have penetrated raim-forest and let in the light 
the tutsan (Hypericum Androsaemum) can gain a footing; also the 
elderberry (Sambucus niger) spreads readily in forest where the 
undergrowth has been more or less destroyed—e.g., on the Dunedin 
Town Belt. In the neighbourhood of Wellington City damaged semi- 
coastal forest will contain the herb-robert (Geranium Robertianum) 
and the aromatic Cedronella triphylla, a Canary Island plant. 
Perhaps the most interesting of all the new plant-associations are 
the indigenous induced, since they demonstrate the extreme aggres- 
siveness of various indigenous species. The following is an especially 
interesting example. : 
A fairly pure plant-association, unknown in primitive New Zea- 
land, is now one of the most striking features of the vegetation 
in certain parts of both Islands. It is also of great economic 
importance. This is the now well-known ‘“‘ Danthonia grassland.” 
In the South Island, from Nelson to the south of Canterbury, it 
