THE WALLFLOWER FAMILY 179 



This is a singular endemic genus, of the detritus fans 

 and upper river-beds of the South Island. Kirk describes N. 

 rosulatum " as one of the most remarkable plants known," 

 but is surely in error when he speaks of it " as now becoming 

 rare owing to the ravages of sheep." The plant is quite 

 common in many sub-alpine districts, and certainly does not 

 appear to be generally attacked by sheep. It is sometimes 

 sought after by the settlers, and taken indoors, on account of 

 the delicious orange-like fragrance of the flowers. 



As the name implies, the leaves are arranged in a rosette — 

 a plant form not unusual in such a habitat (v. Pachycladon 

 p. 178). The structure of the rosette, however, is very 

 remarkable, if not altogether unique. The flower-head, as 

 shown in the photograph on the title page, is much shorter 

 than in the typical form, but the picture gives a much better 

 idea of the character of the rosette than those drawn by 

 previous Mrriters. That given by Mr. and Mrs. Featon in their 

 Art Album of the New Zealand Flora is, particularly misleading, 

 evidently having been drawn by someone who had not seen 

 the plant growing. The leaves overlap like the shingles of a 

 roof, and the whole rosette itself is curved like an umbrella, so 

 that only the outer edges touch the ground. Thus, all rain 

 falling on it, quickly rolls off, and is rapidly conducted through 

 the loose shingle to the long characteristic tap-root, which 

 firmly anchors the plant amongst the drifting pebbles. 

 Underneath the umbrella-like foliage is a cavity, which is not 

 without its value in the economy of the plant. During the 

 day, since the shingle is hot, and the under surface of the plant 

 cool, vapour must then be condensed on the under-surface of 

 the rosette. Thus the leaves obtain a copious supply of 

 moisture throughout the period of insolation. At night the 

 shingle cools down more rapidly than the plant, and 

 condensation now takes place upon the ground. The foliage 

 is thus kept dry, and protected to some extent from the effects 

 of frost. 



