Gillies. — On the Growth of Trees on Scoria Soil. 357 



Habitat. — Port Pegasus, Stewart Island, on wet open ground, ranging 

 from 100 to 1500 feet in elevation. Named in honour of G. M. Thomson, 

 Esq., of the Dunedin High School, who discovered it along with myself. 

 The only other New Zealand species of Ehrharta is an alpine plaut from the 

 Tararua Eange, Wellington. This grass possesses, I should say, no 

 economic value. 



DESCEIPTION OF PLATE X. 



Fig. 1. Ehrharta thomsoni, Petrie. Nat. size. 



2. Spikelet. 



3. Upper pair of empty glumes and floret. 



4. Floret. 



5,5' Nervation of lower pair of empty glumes. 

 6,6' „ upper „ „ 



7. ,, flowering glume. 



8. ,, palea. 

 9,9' Scales. 



10. Grain. 



Aet. Lin. — Notes on the Groioth of certain Trees on Scoria Soil near Mount 

 Eden, Auckland. By T. B. Gillies, a Judge of the Supreme Court 

 of New Zealand. 



[Read before the Auckland Institute, 30th June, 1879.] 



In autumn, 186G, I planted a variety of trees on a piece of scoria land 

 at the foot of Mount Eden, where I had just built my house, and have 

 now (February, 1879) carefully measured them with the following results. 

 The land was wild scoria land, the surface covered with scoria boulders, the 

 partial disintegration of which had formed soil below, in which were also 

 imbedded scoria boulders. At a greater depth were masses of scoria 

 rock and ash partially decomposed and in many places forming rocky 

 cavities. The surface vegetation was grass and fern. The young trees 

 when planted were from one to two feet high, probably two to three -year- old 

 seedlings. Oaks and other deciduous trees did not thrive, and ultimately 

 died off, except the upright poplar, one badly-grown elm, and the weeping 

 wiUow. Peach trees grow ra]oidly and fruit well for a few years (about 

 seven), and then cease to bear. Apple trees grow well and fruit freely for a 

 few years, and then die off from a sort of dry-rot at the roots. Plums, 

 apricots, and cherries do badly in this soil. It will be seen from the 

 annexed table that coniferous trees grow wonderfully in such soil, especially 

 p. insignis and radiata, as also Cupressus macrocarpa, Taxodium semperviretis, 



