332 Ti'ansactions. — Botany. 



ROTOMAHANA. 



Eotomahana is of small size, its greatest diameter being less than a mile. 

 From the numerous swamps which surround it, the absence of wood, the dirty 

 gTeen colour of the water, and the stunted aquatic vegetation which certainly 

 exists under unfavourable circumstances, the first view of this remarkable 

 lake is strangely disappointing. But in a moment all this is forgotten, as 

 landing from the canoe the traveller walks round a projecting point of the 

 swamp and stands at the base of Te Tarata. This paper is, however, 

 concerned only with the vegetation of the locality, and the conditions under 

 which it exists. 



The height of the terraces of Te Tarata is about eighty feet ; at its base is 

 a small clump oi Leptospermum growing amongst Cladium, junceum and other 

 uliginal plants. Nephrodium unitum occurs sparingly, and by careful search 

 a stunted specimen of Gleichenia dicJiofoma, another tropical fern of wide 

 distribution, may perchance be found. G. cirdnata is abundant. Ascending 

 the terraces until the verge of the geyser is reached, Fteris incisa, Lycopodium 

 cermmm, Dianella intermedia, Leucopogon fasciculatum, Haloragis niicrantha, 

 Leptosperonmn ericoides, Gleichenia cirdnata, and var. dicarpa, are found 

 occupying a small rocky knob from which the troubled surface of the fountain 

 may be viewed in safety. The steep upper lip which forms the opposite side 

 of the crater is clothed in many places with a dense growth of Lycopodium 

 cernuwni, large patches of which exhibit a scalded appearance, as if from the 

 effects of over-heated steam. On the opposite side of the terraces Neplir odium 

 unitum covered the thin crust overlying the scalding mud, and from its erect, 

 rigid habit, and strict sori-laden pinnules, presented a forcible contrast to the 

 luxuriant swamp form previously described. Its rbizomes are massed together 

 in dense masses, sufficiently firm to bear the weight of a man, and produce 

 fruited fronds from two inches to two feet high in countless thousands. 



Proceeding for some distance along the shore of the lake and ascending the 

 hill side nearly opposite Rotokiwi the entrance to a small glen known as 

 Rotokanapanapa is attained, and after crossing a patch of steaming mud 

 amongst miniature mud-volcanos in an active condition, the little green pond 

 from which the glen takes its name is seen ; its green colour is doubtless due 

 to the presence of a minute Conferva. The sides of the glen in many places 

 are dotted with steam jets which have destroyed much of the vegetation. In 

 this remarkable habitat Gleichenia dichotoma . attains a luxuriance not to be 

 seen in any other locality in the colony. Where sheltered by low scrub it 

 reaches the extreme height of from five to six feet, and is repeatedly branched. 

 In exposed places it is restricted to a single pair of simple pinnse, but in all 

 cases it is marked by the small accessory pinnse at the base. In several 

 instances steam jets had burst through spots occupied by this fern, and 



