These forests occur in the high rainfall areas of most of the main islands reaching elevations in excess of 1600 m. Like the dry forests, they are often dominated by the ubiquitous endemic Metrosideros polymorpha (Myrtaceae) and can have canopy heights up to 20 m. The great variation seen in Metrosideros polymorpha with foliage colour varying from dark, greenish, grey to bright green and flowers that vary in colour from crimson to light coral red have led to the recognition of a number of varieties. Other characteristic trees include a variety of endemics such as Antidesma platyphyllum (Euphorbiaceae), Bobea timonioides, Hedyotis terminalis, Psychotria hawaiiensis (Rubiaceae), Pisonia sandwicensis (Nyctaginaceae) and Tetraplasandra hawaiensis (Araliaceae). In the relatively undisturbed stands most of the under storey species are also endemic. Typical endemic shrubs include Cyrtandra platyphylla (Gesneraceae), Dubautia scabra (Asteraceae), Hedyotis hillebrandii (Rubiaceae), Lysimachia hillebrandii (Primulaceae), Myrsine sandwicensis (Myrsinaceae) and Vaccinium dentatum (Ericaceae). These forests are also rich in tree ferns with species such as the endemic Cibotium hawaiiense (Dicksoniaceae) together with tall growing ferns of the endemic genus Sadleria such as S. cyatheoides and S. pallida (Blechnaceae).  The many smaller endemic ferns include Athyrium microphyllum (Athyriaceae) and Ctenitis rubiginosa (Dryopteridaceae).  Among the vines, several endemic species of the Lamiaceae are relatively common including Phyllostegia vestita and Stenogyne rugosa, as is the endemic epiphytic shrub Clermontia clermontioides (Campanulaceae), while the rich epiphytic herbaceous flora includes the endemic Astelia menziesiana (Liliaceae) and a multitude of filmy ferns.

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