332 ; Transactions.— Botany. 
ROTOMAHANA. 
Rotomahana 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 
green 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 of Leptospermum growing amongst Cladium junceum and other 
uliginal plants. Nephrodium unitum occurs sparingly, and by careful search 
a stunted specimen of Gleichenia dichotoma, another tropical fern of wide 
distribution, may perchance be found. G. circinata is abundant. Ascending 
the terraces until the verge of the geyser is reached, Pteris incisa, Lycopodium 
cernuum, Dianella intermedia, Leucopogon fasciculatum, Haloragis micrantha, 
Leptospermum ericoides, Gleichenia circinata, 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 
cernuum, large patches of which exhibit a scalded appearance, as if from the 
effects of over-heated steam. On the opposite side of the terraces Nephrodiun. 
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 rhizomes 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. 
Tn exposed places it is restricted to a single pair of simple pinne, but in all 
cases it is marked by the small accessory pinnæ at the base. In several 
instances steam jets had burst through spots occupied by this fern, and 
