154 



Transactions. 



Many introduced plants are found, especially in the stable sand-plain. 

 The tree-lupin (Lupinus arboreus Sims) covers extensive patches on dune 

 and plain. 



Of the forty or so indigenous species found in the field examined, 

 seventeen were selected for anatomical observation, namely, — 



(a.) Gramineae. 



1 . Calamagrostris Billardieri. 



2. Arundo conspicua. 



3. Poa caespitosa. 



4. Festuca littoralis. 



(b.) Cyperaceae. 



5. Scirpus nodosus. 



6. f rondos us. 



7. Car ex pumila. 



(c.) Restionaceae. 



8. Leptocarpus simplex. 



(d.) Thymelaeaceae. 



9. Pimelea arenaria. 



(e.) Myrtaceae. 

 10. Leptospermum scoparium. 



(/.) Onagraceae. 



1 1 . Epilobium Billardie/rianum . 



12. nerterioides. 



(g.) Halorrhagaceae. 



13. Gunner a arenaria. 



(h.) Umbelliferae. 



14. Crantzia lineata. 



(i.) Convolvulaceae. 



15. Calystegia Soldanella. 



(j.) RUBIACEAE. 



16. Copras ma acerosa. 



(k.) COMPOSITAE. 



17. Cassinia fulvida. 



C. Ecological Conditions op the Dune-plants. 



Full details as to New Zealand dune conditions are not necessary here, 

 since they are treated of at length by Cockayne (" Report on the Dune 

 Areas." p. 19 et seq.). 



Some of the more important factors, however, governing the form, &c, 

 of the dune-plants are as follows : — 



1 . Edaphic. 



(a.) Moderately fine quartz sand. 



(b.) Moisture available at all times except for first 5 in. of surface of hills. 



(r.) Hollows much wetter than hills, owing to proximity to water-table, 

 so that water may lie in pools on the surface for considerable periods, especi- 

 ally in winter. 



(d.) Layer of humus in many places, at some yards deep in the hills, but 

 forming an upper thin soil in some of the hollows. 



(e.) Lack of nutritive salts. 



2. Climatic. 



(a.) Prevalent winds at New Brighton: (1) East, from sea ; (2) north- 

 west, hot and dry ; (3) south-west, cold and often bringing rain. 



(b.) Effect of wind : (1 ) Blows sand, thus plants are liable to be buried, 

 and liable to mechanical damage from drifting sand ; (2) cools soil, and 

 causes rapid evaporation : (3) transpiration accelerated. 



(c.) Insolation strong. 



