Vegetation Species Distribution. Where the Napier-Taupo road passes through the gap between the forests of the Huiarau and Ahimanawa Ranges, there is a distinct floristic boundary. Between this and the Kaweka lies the Ahimanawa Range. Dracophyllum latifolium and Phyllocladus trichomanoides do not extend as far south as this line; Phyllocladus glaucus and Gaultheria oppositifolia just reach it, while Quintinia serrata extends a short distance into the Ahimanawa. Ixerba brexioides is not now known south of the road, but has been reported from forest near Puketitiri, now destroyed. Thus there is no northern element in the Kaweka flora. On the other hand, though there is a general relationship with the Ruahine vegetation, several physiognomic species are absent, notably Libocedrus bidwillii, Danthonia cunninghamii and Olearia colensoi. Dacrydium biforme, apart from a solitary doubtfully identified hand specimen, is likewise absent, while Senecio eleganifolius is rare, apparently confined to a few river cliffs in the valley bottom of the head of the Tutaekuri. While the boundaries of Libocedrus and Olearia lie well outside the area, the absence, or virtual absence of Dacrydium is perplexing, as it is prominent on either side in both Ruahine and Ahimanawa Ranges, though not in the Kaimanawa. A comparison with the Northern Kaimanawa suggests that the absence of Danthonia cunninghamii may be due to long continued browsing by deer. A number of species link the Kaweka with the Kaimanawa and the volcanic plateau: Dracophyllum strictum, D. subulatum, Aristotelia fruticosa, Myosotis australis and Caladenia lyallii. To the west Cyathodes colensoi, Coprosma petrei and Carmichaelia orbiculata appear on the upper Taruarau boundary, and Senecio glaucophyllus v. raoulii on the upper Ngaruroro boundary of the Kaweka. An endemic of the Inland Patea, Hebe colensoi, extends to this as well as to the Ruahine and Kaimanawa, but another, Myosotis eximia, does not cross the Taruarau-Ngaruroro boundary. Celmisia incana is shared with the Ruahine and the volcanic plateau, though it is curiously absent from the intervening Kaimanawa Range. Two plants with a limited North Island distribution, Epilobium pychnostachon and Helichrysum depressum, occur in the Kaweka. A prostrate Hebe, not certainly identified, which is confined to exposed shingle slopes, is a possible endemic, and the Kaweka Range is the main centre of distribution of the hairy Pimelea lyallii which extends also on to the Northern Ruahine. Since evidence of the destruction of vegetation by the Taupo shower is clear as far as the main crest of the range, a large part of the area must have been recolonized within the past 1800 years. It may be postulated that chance is a factor in the occurrence and distribution of species, while it is possible that pumice soils may be unfavourable to certain species. Altitudinal Belts These can be reconstructed only sketchily in the eastern and southern parts of the range, as the original vegetation to the highest crests has been affected by grazing and repeated burning between the 1870's and 1905. Most of the northern and western portion, however, has not been touched by fire, and shows four main altitudinal belts, which are here distinguished by their dominant species: 1. Subalpine vegetation, dominated largely by Danthonia tussock. 2. Forest in which mountain beech (Nothofagus cliffortioides) is dominant. 3. Red-beech (N. fusca) or silver-beech (N. menziesii) forest.