Cockayne. — Obscrvatiou.'i on Coastal Vegetation. 319 



contain none of tlie characteristic New Zealand psammaphytes 

 {13; p. 237). But there are a number of differences in New 

 Zealand dunes, and these are sufficiently marked to enable 

 a botanist conversant with the coast to tell within certain limits 

 to what part of New Zealand a particular sandhill would belong. 

 One example will suffice here, and, as it is an interesting case 

 of representative species, it is worth emphasizing. The genus 

 Vassinia is represented in New Zealand by six species, one of 

 which — C. albida. Cockayne — would be considered by many as 

 a variety only, and another, C. amoena, is confiiied to the 

 North Cape. As for the remaining four, all are common at 

 si'a-level, while two of them ascend into the subalpine region. 

 As for their life-forms, they are very similar, being of the cricoid, 

 sclerophyllous type with tomentose leaves. Commencing at 

 the subantarctic islands, C. vauvilliersii occurs near the coast 

 to the south of the South Island, where it is succeeded by C. 

 Jidvida, this in its turn giving place to C. leptophylla in the 

 central pro^^nce, and this to C. retorta in the northern province. 

 Everywhere Scirpus frondosus is the leading sand-binding plant, 

 but in the central and northern provinces this is reinforced b;\' 

 ■Spinifex hirsutus. But no more need be said here as to the 

 above edaphic formations, as they will receive detailed treat- 

 ment in the special part of this scries. 



5. Physiognomy of Coastal Vegetation. 



Formerly the physiognomy of vegetation was merely a 

 geographical concern pure and simple, but this is no longer 

 the case, since it is recognised that the life-form of a plant is 

 a physiological matter depending on the relationship of form 

 to outer factors and to inner causes. This being so, the general 

 appearance of the landscape as determined by the presence of 

 certain dominant species becomes an affair of high biological 

 interest. Now, the scenery may be affected in two ways : either 

 some particular plants or life-forms may be especially striking, 

 or it may be a group or even the character of a whole formation 

 that may specially catch the eye. Thus, taking New Zealand as 

 a whole, the scenery is distinctly affected by the abundance of 

 Cordyline australis and Phormium tenax, while that life-form 

 the " tussock " is perhaps the most striking characteristic of 

 large areas. On the other hand, where forests dominate the 

 landscape their individual members exert little influence, it 

 l>eing their evergreen character and close growth which stamps 

 their physiognomy. 



Coming now to the subject of this section, Cordyline australis, 

 -Phormium tenax, P. cookianum, and tussock - grasses play fre- 

 <|uently quite a prominent part in the physiognomy of the 



