294 Transactions . — Botany. 



end the tree fern, enclosed between these now very thick 

 roots, slowly dies, and Dracophyllum arboreum remains in 

 its place as a forest tree, its former roots now playing 

 the part of a stem. Sometimes a large number of roots 

 growing so closely together as to apparently coalesce make 

 up such a " root-stem," to use a term from a letter of Mr. 

 H. Carse. In one instance where a tree of D. arbo- 

 reum had been felled while making the forest track, thus 

 giving an opportunity for examining its structure, I counted 

 thirty roots, which varied in thickness from 16 cm. bv 7 cm. 

 to 5 cm. by 3 cm., or even smaller, and, as seen from the above 

 measurements, longer in one direction than the other, owing 

 to the pressure, the whole making a "root-stem" 45cm. in 

 diameter. The similar behaviour of certain trees, notably of 

 Panax arboreum, in the New Zealand forest is well known, 

 and the Eev. W. Colenso has gone into the matter at con- 

 siderable length so far as the Seventy-mile Bush, in Hawke's 

 Bay, is concerned (13, p. 252, et sag.). Mr. H. Carse, who 

 very kindly sent me some notes on this subject, taken in the 

 forest near Mauku, Auckland, has written an account of this 

 interesting matter, which I anticipate will appear in this 

 volume, so there is no need to go into the subject at greater 

 length here. 



Dracophyllum arboreum, the dominant tree of the table- 

 land forest, is especially interesting because of the changes 

 which it exhibits during its life-history. In its final form 

 it is a low tree, attaining at times a height of some 9 m. It 

 has a short thick trunk below, and, above, spreading branches 

 bearing masses of needle-shaped leaves, resembling much 

 those of Dracophyllum paludosum before described. Besides 

 occurring in the tableland forest, the tree is found in lowdand 

 swamps and in the drier portions of the bogs, where it marks 

 either a retreat or advance of the present forest. The early 

 seedling leaves are very much broader than the adult, and 

 resemble the seedling leaves of Dracophyllum paludosum, 

 which, however, are rather narrower. The early seedling 

 form persists for a long time in the ODtogeny of the in- 

 dividual, and young plants are quite common loin, in 

 height possessing only the broad leaves, as shown m the 

 photograph I took in the neighbourhood of Lake Te Kua 

 Taupo (Plate XIX.). Usually when a plant has attained 

 to this size it suddenly puts forth leaves of the adult type, 

 and both leaf-forms exist upon the same individual at the 

 same time. As the tree continues to develope all trace of 

 seedling leaves may vanish, and finally there will be a plant 

 merely with the nefedle-like leaves, looking like a very large 

 spreading specimen of Dracophyllum paludosum. Usually, 

 however, many <: reversion shoots " of the most extreme 



