Osmunda regalis L.
royal fern
Rhizomes forming thick erect trunks to 150 cm tall. Fronds 30-300 × 20-75 cm, ovate, 2-pinnate, glabrous except when very young, dimorphic with the outer ones sterile and inner fertile. Fertile fronds bearing sterile pinnae at base and much reduced fertile pinnae at apex. Sterile secondary pinnae in up to 15 pairs, 2-7 × 0.8-1.8 cm, narrowly oblong, obtuse, ± truncate at base, often with a rounded lobe on one side. Fertile secondary pinnae to 3 × 0.4 cm, densely covered with clusters of sporangia.
N.: N. Auckland (Ohinewai), S. Auckland (Coromandel Peninsula, Hauraki plains, lower Waikato Valley, Matakana Id, Matata, Lake Rotoiti), Taranaki (Pohokura Saddle area), Wellington (Rangitikei R.).
Europe, W. Asia, Africa, India, N. and S. America 1890
Swamps, wet ground, streamsides, drains.
This distinctive sp. (Plate 2) has long been established in the swampy areas of the Waikato where some very old plants are known with trunks to 1.7 m diam. Field, H. C., Ferns of New Zealand 145 (1890), discussed the earliest records of this sp. in N.Z., its habit and seasonal growth.