86 NEW ZEALAND PLANTS. 



remain undisturbed, the time would not have been far distant when 

 the Dominion's beautiful vegetation her most special characteristic 

 -would be confined to a comparatively few spots of limited area. 



EVOLUTION OF MEADOWS. 



A very common feature of many parts of New Zealand, especially 

 in the mountainous regions, is a broad, shingly river-bed, bounded 

 on either side by high terraces, or sometimes filling up a narrow valley. 

 The water of these rivers is not usually confined to one channel, but 

 meanders in several narrow streams over the wide stony bed, which 

 in consequence is in places quite dry, and ready for plant-colonists. 

 These are not slow to avail themselves of the chance to ' take up 

 land," and engage the wind or the birds to convey them to their new 

 holdings, while some even travel by water. 



Amongst the earliest settlers are the willow-herbs (Epilobium) , 

 thanks to their light seeds furnished each with a tuft of hairs. Various 

 species of Eaoulia come in a similar manner, and large, round, moss- 

 like cushions or patches of silver and green result (Raoulia australis, 

 R. tenuicaulis, R. Haastii). Lichens cover the stones with curious 

 markings, and mosses spring up between them. As these earlier 

 plants decay, humus is added to the silty, sandy soil, and vari- 

 ous drought-resisting shrubs (Discaria toumatou, Cassinia fulvida. 

 species of Carmichaeliq) put in an appearance, together with grass- 

 tussocks. Such shrubs may remain quite isolated, and the tus- 

 sock become dominant, in which case the shelter will favour the 

 settlement of many small herbaceous plants, including grasses, and 

 a meadow will result. Or, on the other hand, some condition may 

 favour arborescent growth - - a natural shrubbery of veronicas, co- 

 prosmas, and other shrubs with wiry branches may appear, to be 

 replaced finally by a beech forest. Meadows formed in this manner 

 may be seen in process of evolution in many places, and it was in 

 this way that the great river-made plains, equally with the "fans' 

 of debris at the outlet of creeks, have been colonised by their plant 

 inhabitants. When the forest on a hillside has been burnt, if there 

 are frequent winds, trees cannot be reinstated, and meadow will 

 result. Such fires have been frequent even in the pie-European 

 days. Grasses, especially drought-resisting species, will have a much 

 better chance of growth than trees after a fire, and a meadow will in 

 an astonishingly short time replace the forest. This replacement is 



