Botanical Subdivisions of the Province of Marlborough.

All that part of Marlborough west of the Wairau River and north from Tophouse belongs to the Sounds-Nelson Botanical District as defined by Cockayne and Allan (1914, pp. 19–20). The boundary-line between the North-eastern and the North-western Botanical Districts has been defined by Cockayne (1916, p. 195) as following the line marking the average limit of the western rainfall between Hanmer in the south and Lake Rotoiti in the north, but its position has never been more precisely determined. In a forthcoming paper the writer hopes to review the evidence on which he bases his view that that portion of Marlborough comprising the mountainous country of the Bounds and Raglan Ranges forms part of the North-western District. Thus, for the purposes of this paper, the western boundary of the North-eastern District is deemed to be a line following the Wairau River from its mouth as far as Mount Patriarch, then turning east to Mount Bounds and following the Waihopai

River to its source, and thence south by the Acheron River to the Clarence River. Though not strictly forming part of the Province of Marlborough, it has been found expedient to include the St. Arnaud Range in the scope of the present review. Thus the province has been subdivided so as to incorporate portions of three botanical districts, each with species and varieties not to be found elsewhere in Marlborough.