Abstract
While Volumes I and II of Flora of New Zealand were concerned only with native plants, Volume III describes the introduced wild plants belonging to the rush, sedge, lily, iris, arum and related families, the first comprehensive account of these plants since H. H. Allan' s Handbook of the Naturalized Flora of New Zealand of 1940.
Volume III is a "weed flora". Much of the text is devoted to two large groups, the rushes and the sedges with their green or brown insignificant flowers, which are always a problem in agriculture, difficult to identify individually, and in which the native species cannot easily be distinguished from introduced ones and are equally weedy. In contrast many garden plants of the lily, iris and related families are included, ones which have escaped into the wild. They make splashes of colour on roadsides and waste places, and among the brightest are watsonia, montbretia, wild ginger, and Kaffir lily [Editorial note: used historically, no longer used as it is offensive.]. Then there are the "dangerous" weeds — Cape tulip, toxic to man and animals; Australian sedge, invading pastures; and water hyacinth and "oxygen weeds" dangerous to waterways. The plants originate from all countries of the world, but a large proportion of the garden escapes are from South Africa, and many rushes and sedges come from Australia or America.
This book is an identification manual, intended for agriculturalists concerned with weed control, for botanists making vegetation surveys, for anyone, in fact, who needs to identify these weedy plants. Keys cover monocotyledonous introduced and native genera (except grasses), and introduced and native species when both occur in the same genus. There is also a key to families and some genera based mainly on vegetative characters. Historical background too is provided, for the plants have been an ever-increasing component of the flora of New Zealand. For each species the first published record of its occurrence in New Zealand is cited, together with the present known distribution. The mode of dispersal and other ecological data relating to the more aggressive species are discussed, and comments on their significance as weeds are included.
