110 



CHAPTER XIII. 



THE FERNS OF TUTIRA. 



THE ferns of Tutira deserve special attention a chapter, albeit a brief 

 one, to themselves. Out of the 135 species enumerated by Cheeseman 

 in his 'Manual of the New Zealand Flora,' or 134 if the very doubtful 

 Davallia Forsteri be disallowed, more than one-half grow on Tutira. It 

 is a remarkable record for one station a record which, I am confident, 

 can never be exceeded. Variations of altitude, large rainfall, range of 

 climatic conditions, dissimilarity of geological formations, and careful 

 search have each in its degree contributed to this result. The main 

 cause, however, has been the wild and rugged nature of the country, 

 its enormous quantity of gorges and ravines, its hundreds of miles of 

 precipice and crag. Species ousted elsewhere maintain themselves in 

 such spots they afford a last foothold to fugitives ; thus, clinging to 

 the base of a low conglomerate cliff, survives a patch of Gleichenia 

 circinata. Twice have fires almost blasted the plant to death ; twice 

 has it reappeared. A dripping precipice, otherwise usurped by Poly- 

 podium Billardieri, shelters Lindsaya viridis ; crannies in a single mass 

 of broken limestone rock high on Heru-o-Tureia afford foothold to 

 Cystopteris fragilis ; the concave base of a series of high, dry con- 

 glomerate rock- faces safeguards Doodia media ; though nibbled and 

 brushed by stock, and though endangered during every flood by land- 

 slips, it survives. The low rims of a tumbled mass of conglomerate 

 boulders offer a last foothold to Adiantum diaphanum. It has climbed by 

 an athletic feat from its own natural habitat the forest floor. Asplenium 

 Trichomanes survives on a single limestone rock broken from one of 

 the ancient sea -floors of eastern Tutira and deeply set in the turf of 

 the green hillside. Each of the above species has been found but on 



