June in the hills with Chris Horne and Barbara Mitcalfe
Dicksonia fibrosa, whekī-ponga
You canít miss this handsome, endemic, tree fern with its massive, reddish-brown trunk up to 60 cm in diameter covered by thickly matted fibres. It grows to 6 m tall with a crown of living fronds arising at a steep angle. Up to 3 m long, they are dark-green above, paler below, harsh when you clutch one and densely hairy at the base. Below the crown hangs a tightly-belted, strikingly voluminous skirt of complete, grey-brown, dead fronds, which accumulate there, lasting for years, obscuring the upper part of the trunk.
Whekī-ponga is a sub-canopy species that prefers fertile, silty, soils near rivers in lowland to montane forest, or semi-open country in the North Island from Auckland southwards. It is mostly coastal and lowland in the South, Stewart and Chatham islands. Uncommon in Wellington city, there are examples in Otari-Wiltonís Bush, Karori Sanctuary, and Burrows Avenue Reserve, Karori. You will also see several in Riverstone Terraces Reserve, between Moonshine Road and the Whakatikei River, on the track above the true right bank of the Hutt River.
You may remember reading in the May Tramper article, about whekī-ponga's close relative, Dicksonia squarrosa / whekī. The presence of hairs on the stalks distinguishes the Dicksonia genus from the only other NZ tree-fern genus, Cyathea, which has hairs and scales Ė see the articles in the March and April issues of The Tramper.
The genus Dicksonia, is named after an 18th - century English botanist, James Dickson. The species name, fibrosa, refers to the thickly matted fibres covering the trunk.
We have not found any rongoā (medicinal) uses of whekī-ponga. If you know of any, please let us know.
Because the tough fibres effectively deterred rats, Māori split the whekī-ponga trunks to form slabs for lining buildings, e.g., pātaka / food stores, or forming food-storage platforms placed on top of posts.