412 PLANTS OF NEW ZEALAND 



Islands, the leaves show great variation in several respects. The proportions, 

 and actual size, not only vary largely, but some bear abundant tomentum on the 

 upper surfaces, there being none in others. Three plants growing side by side 

 in the vicinity of Lake Rangatapu might readily have been taken for distinct 

 species, yet the conditions under which they were growing appeared to be the 

 same. 



In large genera, such as Veronica and Coprosma, the 

 variabiHty is so great that it is most difficult to fix the 

 limits of the species. The same difficulty presents itself in 

 Olearia ; but will to some extent be removed when our 

 knowledge of the genus is fuller than at present. Several 

 species are known only from a few specimens, and others are 

 extremely local in their distribution. This is the more 

 remarkable, as the pappus with which the seeds are provided 

 is eminently calculated to scatter the species widely. Some 

 of the finest plants in the genus are endemic in the off-islands. 

 Thus 0. semidentata is found only on the Chatham Islands. 

 It bears handsome flowers of a bright purple, whose colour is 

 a striking contrast to the white of other species. According 

 to Mr. Cox, a white-rayed form is, however, sometimes found. 

 But this is not the only Olearia endemic to these islands, 

 O. Chathamica, which somewhat resembles the magnificent 

 O. angustifolia and 0. Traversii, with opposite leaves, are also 

 found nowhere else. The latter was originally mistaken by 

 Dieftenbach for the Mangrove (Avicennia officinalis), which it 

 slightly resembles. Many specimens of it are to be seen in 

 the Christchurch Gardens, and there are also several well- 

 grown plants beside the Hereford Street Bridge in the same 

 town. 0. operina is only known from the Sounds on the 

 West Coast of Otago. 0. angustifolia — a beautiful plant, 

 whose flowers have white rays and a violet disk is found 

 chiefly in exposed places near Paterson's Inlet (Stewart 

 Island), though it has been reported from south-west Otago. 

 0. Traillii, another noble species, is known only from one or 

 two localities on the mountains at the head of Paterson's 

 Inlet ; 0. Li/allii is endemic in the Snares and Auckland 



