46 MR. W. В. B. OLIVER ON THE 
In many places the ground is undermined by Petrels, and here is usually a 
luxuriant growth of grass and herbs. In vacant portions of the clearings 
made by Gannets, there is likewise a rank growth of herbaceous plants. 
The soil in those portions occupied by sea-birds must contain a considerable 
quantity of guano ; elsewhere it is a rocky surface with no humus. 
The vegetation on the coastal cliffs and slopes not frequented by sea- 
birds is an open formation. Here оссиг small detached patches or single 
plants of a low, apparently tufted fern CHistiopteris incisa, Ag.), a tussock 
grass (Роа anceps, Vorst. var condensata, Cheesem.), and the trailing succulent 
plant Mesembryantheum australe, Soland. Small shrubs of Metrosideros 
tomentosa also occur here. Histiopteris incisa in these situations has small 
fleshy fronds usually lacerated or dead at the margins. Poa anceps var. con- 
densata is stunted and tufted with dense contracted panicles, 
A close meadow formation occurs in those areas annually occupied by sea- 
birds. Near the Gannet colonies is a rank growth, under half a metre tall, 
of herbaceous plants. The principal species are Chenopodium triandrum, 
Forst., and Sonchus oleraceus, Linn., each occurring in distinct patches. On 
the slopes undermined by Petrels there is usually a dense growth of tangled 
grass (Poa aneeps var. condensata), large patches of the succulent Mesem- 
bryanthemum australe, with small clumps of a low creeping fern ( Histiopteris 
incisa), and here and there a small shrub of Metrosideros tomentosa or 
Coprosma Baueri. 
List or SPECIES. 
Histiopteris incisa (Thunb.), J. Sm. 
Coastal cliffs and rocks. 
Widely distributed in tropical and south temperate regions, 
Poa anceps, Forst. #., var. condensata, Cheesem. 
Coastal eliffs and rocks. 
New Zealand as far south as Canterbury. 
Deyeuxia Forsteri, Kunth. 
Shingle beach (rare). 
New Zealand, Tasmania, Australia. 
Phormium tenax, Forst. 
Outer edge of serub (not common). 
New Zealand, from Auckland Island north to Norfolk Island. 
Chenopodium triandrum, Forst. f. 
Near Gannets. 
New Zealand. 
Mesembryanthemum australe, Soland. 
Coastal eliffs and rocks. 
New Zealand, Tasmania, Australia. 
