We review the biosystematics, chemistry, phenology, ecology, and cultural and economic uses of Phormium tenax, a widespread iconic New Zealand monocotyledon. Phormium tenax is endemic to New Zealand, Norfolk Island, and the Chatham Islands, and is distinguished from the sole other members of the genus, P. cooking, by its erect trigonous seed capsules and red flowers, despite incomplete barriers to hybridization. Flowers produce abundant nectar and are bird pollinated. Seed is orthodox and tolerates drying while chilling overcome dormancy. Rich, well-drained alluvial and organic soils encourage abundant growth in P.tenax but prolonged flooding and drought reduce growth and survival. Lack of tolerance to both frost and low mean annual temperatures distinguishes its environmental niche from that of P. cooking, but further research is required to characterize these differences more accurately. Phormium tenax is a significant component of vegetation on coastal cliffs, slopes, and dunelands; in estuarine shrublands; and lake margin and freshwater communities. Wide morphological variation in Phormium has led to cultivar development by Maori for weaving and by horticulturalists for ornamental garden use. Phormium tenax is important in many ecological communities as a food source and is often used in restoration and revegetation plantings.
