Cockayne. — Plants of Chatham Island. 285 



scattered about here and there. Just where the Sphagnum 

 formation abuts on the Lepyrodia formation stunted plants of 

 Olearia semidentata and Dracophyllum paludosum, two very 

 characteristic plants of this latter formation, make their 

 appearance, showing the line of tension between the two 

 formations. Growing on the Sphagnum the two plants 

 mentioned above remain very small, and often flower when 

 only 10 cm. or less in height. Similar dwarf plants are 

 common in peat bogs elsewhere, Professor Conway McMillan, 

 for instance, mentioning spruce-trees in the bogs of Minne- 

 sota seventy-five years old, and but little more than l^in. in 

 diameter (44, p. 460). It must have been such miniature 

 plants of Dracophyllum paludosum that Buchanan referred 

 to Drac. rosmarinifolium in his list of Chatham Island plants 

 (3, p. 338). 



In the bog on the Whangamarino Eun the Sphagnum 

 forms large rounded mounds, on which grow many plants of 

 Gleichcnia circinata and a few of Pteris esculenta. Growing 

 in the hollows between the Sphagnum mounds are Myrio- 

 phyllum pedunculatum, Drosera binata, Utricularia mou- 

 anthos, Pratia arenaria, and Poa chathamica. In many 

 places the Sj)hagnum becomes less abundant ; here the soil 

 consists of imperfectly decomposed remains of moss and other 

 vegetable matter 1-2 cm. in depth, below which is black 

 rather sticky peat of a fairly firm consistency. In the upper 

 layer Myriophyllum, growing to a height of 45cm., and 

 forming a dense mat on the ground, stretches its rhizomes, 

 while its roots penetrate for a distance of 5 cm. into the black 

 peat. Growing through the Myriophyllum are many tufts 

 of the Isolepis and Eleocharis gracillima. In places the 

 Isolepis becomes so abundant as to almost conceal the Myrio- 

 phyllum. At times also that extraordinary fern Schizcea fis- 

 tulosa puts in an appearance. Where the Sphagnum appears 

 the substratum is much wetter, the decayed remains of the 

 Sphagnum being wringing wet. In such places Isolepis almost 

 altogether replaces Myriophyllum. Where the ground is a 

 little drier Gleichcnia circinata forms an unbroken sheet ; and 

 growing in company with it are all the bog plants enumerated 

 above, together also with many stunted plants of Dracophyl- 

 lum paludosum, like those before described. Many of these 

 latter tiny plants were in full bloom. 



Lepyrodia- Olearia Bog. 



This formation appears to follow on directly after the 

 Sphagnum, so soon as the ground has become a shade drier. 

 It is now altogether a more common formation than the 

 Sphagnum proper, but it also is rapidly being destroyed, 

 chiefly through the agency of fires. Although Lepyrodia 



