18 Transactions. 



water-plant, the stem is straight, unbranched, and perhaps 40cm. long; the 

 internodes are long ; the leaves linear and entire, and the roots numerous 

 and 30— 10 cm. long ; when the shoot rises above the water-surface it 

 branches, and the leaves are much as in the land-plant. 



Not only the leaves but also the inflorescence differ greatly in size in 

 the land and water forms of the introduced Badieula Nasturtium -aquaticum 

 Brit. & Rend. 



Specially moist air causes the production of aereal roots on the stems 

 of certain whipcord veronicas. 



Schefflera digitata Forst. (Araliac), a low forest tree or shrub, when 

 growing in certain damp gullies of northern Auckland produces sometimes 

 leaves much more deeply cut than the normal. 



The moist-gully form and the dry- or acid-ground form of Bkcknum 

 capense Schlcht. (Filic.) are so distinct in appearance that many might 

 consider them distinct species. 



(e.) Altitude. 



Altitude is a complex combination of factors which sometimes produces 

 striking differences in the same species, according to the height at which 

 the individuals grow. 



A very common feature is diminution of stature with increase of alti- 

 tude, though this is not so with all species. The trees Dacrydium cupres- 

 sinum Sol., Weinmannia racemosa Linn, f., and Griselinia littoralis Raoul 

 are much reduced in size when forming a part of the mountain-scrub of 

 Stewart Island, the two latter eventually becoming small shrubs. 



On the other hand, if the lowlands can offer an equivalent environment 

 to that of the mountains — though, of course, it can never be actually 

 identical — alpine plants may occur at sea-level,, their forms differing not 

 at all from those at an altitude of 600 m., 900 m., or considerably higher. 

 The lowland moor of Stewart Island contains various alpine plants of 

 this character — e.g., Celmisia argentea T. Kirk, Astelia linearis Hook, f., 

 Dracophyllum politum Cockayne, Carpha alpina R. Br., Donatia novae- 

 zelandiae Hook, f., Caltha novae-zelandiae Hook, f., Gaimardia ciliata 

 Hook. f. (For full list, see Cockayne, 1909, p. 27.) 



1. After-effect of Stimuli. 



It is most important with regard to the question of the ultimate heredity 

 of changes in form and structure, &c, brought about by an internal re- 

 sponse of the plant to stimuli from without to inquire as to definite 

 examples where the form, &c, persists for a reasonably long time after 

 the stimulus is removed. The following cases bear on this subject : — 



1. A prostrate form of a species of Coprosma (Rubiac), which originally 

 grew on acid peat on the Chatham Island tableland, was cultivated by 

 me in a pot for three years, and then in ordinary garden-soil in a garden 

 for four years more, during the whole of which time the prostrate habit 

 remained. But all on a sudden, during the eighth year, it commenced 

 to put forth erect shoots, and but for its unfortunate destruction would 

 undoubtedly by this time have been on erect shrub. So assured was I 

 that this plant would remain prostrate or stunted that I published cer- 

 tain remarks to that effect (1907, p. 378). So, too, with a stunted form 

 of another species of Coprosma, perhaps C. cuneata Hook, f., collected 

 by me in 1903 in Antipodes Island. This was grown on the rockery at 



