May in the hills with Michele Dickson and Chris Horne
Gahnia pauciflora, māpere, cutting sedge
Many trampers have suffered cuts on their legs and hands after pushing past this sedge whose leaves have sharp edges. In form, it looks a little like the large grasses e.g., toetoe and introduced pampas, but the culms/stems are so different that you can identify it at a glance. For differences between sedges and grasses, see also the sedge Carex uncinata in the June 2012 In the Hills.
There are six species in the Gahnia genus in NZ, all of them endemic. They are among the largest sedges in NZ. In the Wellington area, the two species you are most likely to see are G. pauciflora and G. setifolia, which will be described in June. Gahnia species are host and food plants for the rare forest ringlet butterfly (Dodonidia helmsii). When chewed gently, the dark-coloured nuts have a raspberry-like or vanilla flavour, depending on perception.
Origin of the names
Gahnia is named after Swedish botanist, Henric Gahn (1747-1816); pauciflora means few-flowered. Distribution and habitat Māpere is present in Te Ika a Māui/North Island and in Marlborough and Nelson in Te Waipounamu/South Island. It likes clay and grows usually in forest or shrub land from sea level to 750 m.
G. paucifolia forms loosely tufted clumps up to about 90 cm high, which arise from short rhizomes. The long thin leaves, with rough cutting edges narrow to a thin point. Culms/stems rise well above the clumps of leaves, up to 120 cm, with few branches. They bear reddish-brown panicles/flowering stalks, which initially rise up at an angle from the clump, then droop with maturity. These can remain for up to two years. The plants are bright-green perennials.
Māpere flowers from December to January. Insignificant tiny flowers with both male and female parts, only some of which are fertile, each bear one fruit which becomes a very hard nut enclosed by a dark brown chaffy covering. The nut is a hard outer coating fused with the seed. Nuts are spindle-shaped, often grooved, sub-triangular in the middle and range in size from 5.5-7 mm long x 2-3 mm wide. The colour changes from an immature yellow-cream to a mature brownish-orange with a dark black tip always present.
We have been unable to find any rongoā/medicinal or other uses of Gahnia pauciflora. If you know of any, please tell us.
Where to find māpere
Look for it in the Aorangi, Remutaka and Tararua ranges, and the Eastbourne and Eastern Hutt hills, particularly in places with light overhead cover.