October in the hills with Michele Dickson and Chris Horne
Lastreopsis glabella, , Smooth shield fern
Lastreopsis glabella is the last of the three locally occurring similar-looking ferns in the Lastreopsis genus that we are describing. Some New Zealand botanists have recently moved this species to the genus Parapolystichum, but existing published books and lists name it as Lastreopsis, which belongs in the large fern family Dryopteridaceae. This species is notable for its smooth stalk/stipe which distinguishes it from the other two species.
Origin of the botanical name
Lastreopsis means like ‘lastrea’, a fern known to the ancient Greeks, and ‘opsis’ from the Greek word meaning ‘looks like’; ‘glabella’ comes from the Latin word ‘glabellus’ meaning ‘hairless, smooth’. Lastrea was named after Austrian botanist Charles Jean Louis Delastre (1792-1859).
Distribution and habitat
Smooth shield fern is common on Te Ika a Māui/North Island, on Te Waipounamu/South Island, on Rakiura/Stewart Island and Rēkohu/Chatham Island. Look for this common fern in damp coastal or lower forests on stream-sides, banks or among rocks. Smooth shield fern is endemic to New Zealand.
Smooth shield fern is a terrestrial fern with erect rhizomes, i.e. the rhizome doesn’t creep or climb but just forms a small mass from which the stipes grow. The three-pinnate, dark-green, oval fronds are 10 cm-35 cm long x 5 cm-25 cm wide. They have a thin but firm feel with flat brown scales at the base of the rachis (frond stalk) and reddishbrown hairs on the upper surfaces of veins and midribs, but hairless elsewhere. The stalks/stipes (stalk beneath the frond) are 3 cm-30 cm long. The stalks, stems/rachises are hairless and smooth. Run your fingers up or down a stalk to feel the smooth surface.
When mature, clusters of sporangia make up the round sori on the underside of the fronds. These are in one row either side of the midrib away from segment/pinna margins. At first they are covered by a kidney-shaped covering/indusium which falls off as the spores ripen. The spores are spread by the wind.
We have not found any records of uses of smooth shield fern. Please tell us if you know of one.
Where to find smooth shield fern?
You can see smooth shield fern in Burrows Avenue and Johnston Hill reserves, Karori, Huntleigh Park, Crofton Downs, Ōtari-Wilton’s Bush, Wellington Botanic Garden’s bush areas, Khandallah Park, Centennial Park, Miramar and Zealandia. It also occurs in Hayward Scenic Reserve, Lower Hutt, East Harbour Regional Park, Akatarawa Forest and the Tararua, Remutaka and Aorangi ranges