Some remarks are here offered as to the general characteristics of the vegetation of the district. The florula is comparatively limited in species, no doubt for the following main reasons:—

A few remarks will be offered under each head:

(1) High evaporation rate.—In spite of the huge rainfall, averaging about 180 inches in the year, the atmosphere is a dry one, and the plants are those of a comparatively dry area. This somewhat paradoxical fact is due to the effect of the mountain range on the moisture contained in the prevailing northwest wind. As the wind-descends the Southern Alps it becomes warmer, and rises higher and higher in temperature above the dew point, so that finally the rate of evaporation becomes extremely high. Unfortunately no records-are available to illustrate this, but there can be no doubt that in spite of the high precipitation the atmosphere is usually dry. The rainfall as recorded at the Arthurs Pass Railway Station from 1924-1927 is as follows: 1924, 160 in.; 1925, 201 in.; 1926, 205 in.; 1927, 171 in. As a rule the rain, which comes mostly from the northwest, falls heavily and disappears quickly. On one occasion 17 in. fell in twenty-four hours, but the very heavy rainfall does not preclude occasional periods of drought. Thus in January 1928 the rainfall was considerably under an inch, and for the first three months of 1928 it was only 14 in. During January the vegetation was in many places parched or even killed, and the rain of March and February fell in short periods of time. During the whole period the streams were unprecedentedly low. On the other hand, in the first three months of 1927, 58 in. of rain fell. An illustration of abnormal evaporation may be given. Mr. S. Page informs us that he has seen light rain falling from a low cloud at Arthurs Pass to within ten or twelve feet of the ground and then evaporating. This unusual phenomenon was doubtless exceptional, but it, and the slow rusting of iron that is apparent, obviously could only occur with an exceptionally high rate of evaporation. The complete absence of miro, matai, rimu, and kamahi, and almost complete absence of rata, though all of these are abundant in the Otira Valley, are no doubt in part due to this cause. Similarly the larger and softer-leaved coprosmas and olearias are chiefly confined to the western side of the range, or the higher valleys on the eastern aide; e.g. Olearia Colensoi is almost entirely a plant of the west, Coprosma lucida is abundant in the Otira Valley, but so far only one plant has been found on the eastern side. Generally speaking the forest and sub-alpine scrub of the eastern side consists of small-leaved plants.

(2) Lack of Soil—As the hillsides and valleys are up to about 4,000 ft. or 4,500 ft. everywhere covered with loose shingle, in places overlain by two or three inches of soil, the rain rapidly sinks through

below the surface-level, and much of it passes away in under-ground streams. The lack of soil tends to limitation of species, and the limitation of species tends m turn to lack of soil. It is only in flat places, therefore, which soon turn into bog, that the ground is always damp, though bog may also be found on hillsides near stream courses, near under-ground streams, or where there is no surf ace shingle. The result is that the vegetation of the hillsides is generally xerophytic. Such plants of dry districts as Exocarpus Bidwillii, Hebe Lycopodioides, Discaria toumatou, are abundant in certain situations within the valley. Here and there on the river-valleys there is a comparatively deep rich soil, no doubt formed in succession from some old sphagnum bog, but the steepness of the hills and the presence of boulders, angular rocks, and shingle slopes apparently prevent the accumulation of humus elsewhere. Another contributing factor is the almost complete absence of dust from the atmosphere, so that even the river-bed raoulias do not develop the thick cushions that, they do in the lower plains, where the abundant dust blown before the northwest wind-storms tends to build them up into ever higher and higher cushions. Raoulia australis and R. tenuicaulis here lie flat on the ground, though R. Haastii forms cushions up to 3 or 4 inches in thickness. Where the river-bed is not subject to floods, under the thin layer of humus may be found four or six inches of clay. Only in the older bogs or in soil consolidated from these bogs is there any depth of humus.

(3) Low winter temperatures.—Another factor limiting the number of species present is the extreme winter cold, due in part to altitude, in part to the fact that there are here narrow valleys shut in on all sides by mountain ridges, and in part to the proximity of high snow-covered mountain peaks. The area dealt with lies roughly between 2,200ft. altitude and 6,000 ft., the limit of vegetation, though several plants have been found at 7,000 ft. on Mount Rolleston. This, which is the dominating peak of the district, is roughly 7,400 ft. in height. Unfortunately again no figures are available for winter temperatures, though a minimum thermometer has now been placed in the district; but there can be no doubt that in winter frosts the thermometer falls to zero Fahrenheit. In the winter of 1925 snow fell to the depth of 2 ft. 6 ins. in the settlement (2,400 ft. elevation), and of 3 to 5 ft. in the col of the pass (3,000 ft. elevation). This was undoubtedly exceptional, for as a result a snow-field was formed in the head of the Bealey river, which as it slipped downwards bore away the Nothofagus forest, trees being destroyed which had been growing from twenty-five to forty years.

(4) Wind.—For about nine months in the year the area is subject to strong, sometimes violent, gales from the northwest. The months of May, June and July, are usually fairly calm. The only other wind that is at all prevalent is the southwester which alternates with the northwest; but probably there is only one day southwest for every three days of northwest wind. Of course the direction of the winds is largely controlled by the direction of the valleys, so that in Bealey valley the southwester of the plains is approximately southeast in direction. Though there is little evidence in storm-

twisted or brush-back trees, of the general direction of the wind, it is undoubtedly one of the factors in limiting forest growth; and the absence of forest from the sides of the hills at the top of the pass in evidently in part due to the strength of the winds there. Usually the forest line lies between 4,000 and 4,500 ft.; but here it is only 3, 000, ft. The winds must of course immensely increase the rate of evaporation and so add to the dry ness of atmosphere.

(5) The effect of the Nothofagus forest on undergrowth.—It is well known that the Nothofagus forests are freer from undergrowth than any other type of New Zealand forest. In the lower Mingha valley the forest is nearly pure Nothofagus cliffortioides. In the Bealey proper there is a much greater intermixture of species. Where the dry hard beech-leaves fall and accumulate and there is a heavy canopy of beech branches overhead, little undergrowth apparently can exist. The beech-leaves only slowly turn into humus, and no good seed-bed is formed. Though not so prejudicial to growth as pine needles, they seem to have a similar effect. Owing to the ravages of man in the Bealey valley, and in more recent years to those of a bud-burrowing larva, the beech forest has suffered much, resulting in a greater and greater development of undergrowth. At present indeed insect larvae are doing much harm to many different species, those especially attacked are Nothofagus cliffortioides, Phyllocladus alpinus, species of Coriaria and Ranunculus Lyallii. Hoheria glabrata is also subject to pests, but comes up in large quantities where the beech has been cut down. It is not intended to discuss the problems of succession here, but merely to indicate that the forest is by no means stable. Obviously under conditions such as those described, the ordinary coastal vegetation of such an area as Banks Peninsula cannot exist, and consequently we find that the forest trees and shrubs of the coastal area are for the most part absent here. Thus tree-ferns are unrepresented except by the low-growing Alsophila Colensoi, and only three species of filmy fern have so far been discovered, though many species are abundant at Otira. Hedycarya, Carpodetus, Pittosporum eugenioides, species of Sophora, Pennantia corymbosa, Melicytus ramiflorus, Hoheria angustifolia, Plagianthus betulinus, Schefflera digitata, Nothopanax arboreum, and other common trees and shrubs of the coastal area are missing here. Indeed the only conspicuous forest trees of Banks Peninsula to be found in the Bealey watershed are Griselinia littoralis, Aristotelia serrata (chiefly in sheltered gullies), and Fuchsia excorticata. The two latter no doubt owe their presence to the fact that one is partly and the other totally deciduous in winter. Of course these differences in the lowland and sub-alpine forests are known to all observers, but we think it well to call special attention to them in order to emphasize the existence of the conditions that we are dealing with. Mention should also be made of the almost total absence of lianes and phanerogamic epiphytes; Clematis indivisa for example occurs in the Otira Gorge but not in the upper Bealey Valley; Muehlenbeckia australis is also absent, and the only lianes or scramblers common are two species of Rubus. There are also so far as noted no flowering epiphytes here, the forest in consequence having none of that sub-tropical appearance so frequently noted in the New Zealand

We have accepted uncinata as the correct specific name, as was done by Kukenthal, because we consider that the name uncinata is sufficiently distinct from Uncinia. Furthermore it is probable that article 55 of the International Rules will be amended at the Botanical Congress of 1930.

Some of the specimens collected possess five sepals, others four sepals. Whether the number of sepals is variable in this species or the specimens with four sepals should be referred to C. monticola Petrie we leave for future investigation.

We are unable to refer this form which is fairly abundant to any described species and refrain from describing it as new, until the whole of the New Zealand species are revised.