Common Names

Mountain toatoa (Silba 1986).

Taxonomic notes

Syn: P. aspleniifolius var. alpinus (Silba 1986), P. trichomanoides var. alpina Parlatore 1868. Type locality: Nelson. P. alpinus is polymorphic and possibly several varieties with different geographical ranges are included in the present description. Adequate comparison of New Zealand forms with those of the Tasmanian P. aspleniifolius have not been made (Allan 1961).

Description

Monoecious, strongly aromatic shrub or tree up to 9 m tall, trunk short, up to 40 cm in diameter. True leaves occur only on seedlings and occasionally on young plants. They are narrow-linear, acute, deciduous, up to 1.5 cm long, on older plants shorter. Phylloclades alternate to subopposite, rhachis short. Phylloclades of juvenile plants up to 2 cm long, deeply divided, thin, with narrow-linear segments, glaucous below; of adults thick, coriaceous, 1-2.5 cm, occasionally up to 6 cm long, 2 cm wide. Phylloclade shape various; narrow-rhomboid or spathulate, sparingly or much lobed, often elliptic to obovate, cuneate at base, apex subacute to broad-obtuse, margins crenate, leaf-denticles small. Pollen cones 5-6 mm long in fascicles of 2-5, rarely solitary, apical, with pedicels 1-2 mm long; sporophylls with small variously shaped apiculi, stems erose. Female cones arise along the margins or on the stalks of the phylloclades; receptacle of red, fleshy scales; mature heads ca. 6-7 mm diameter. Seeds nutlike, black, exserted, ovoid, compressed, ca. 2.5 mm long, obtuse; cupule white, irregularly lobed, up to 2/3 length of seed (Allan 1961, Salmon 1996).

Range

New Zealand: N and S Islands from latitude 36° 50' southwards. It is found on the Coromandel Peninsula between Cape Colville and Te Aroha and from the volcanic plateau southwards between 900 m and 1,600 m to Mt Cargill, Fiordland and Southland. In South Westland and Southland it occurs down to sea level. It occurs in subalpine and scrub forest; also lowland forest in west of S Island. The wood is elastic, making the plant very wind-resistant (Allan 1961, Salmon 1996).

Big Tree

Oldest

One tree-ring chronology, presumably based on living tree material, covers 259 years (data on file with ITRDB).

Dendrochronology

Development of tree-ring chronologies apparently began a collection in the 1970s at Pegleg Creek (S Island: 42°S, 171°E; 279 years) by Dunwiddie (1979). P. alpinus tree ring data have been used in a study of climate change in New Zealand over the last thousand years (Burrows & Greenland 1979). The most recent survey of dendrochronological work with the species is provided by Norton & Palmer (1992).

Ethnobotany

Observations

This species is very common in the alpine and subalpine shrublands and adjacent montane forests of Tongariro National Park. It can be seen from the north trailhead up to Ketetahi Hut on the Tongariro Crossing, and on all of the walks along the Bruce Road and around Whakapapa Village on Mount Ruapehu. It is probably found on most other subalpine scrub trails in the Ruapehu area as well. The walk up to Ketetahi Hut is particularly interesting because the mountain toatoa grows as a forest tree up to about 9 m tall beneath taller trees (including Podocarpus cunninghamii) near the start of the walk, and diminishes in stature as the track climbs upward until it is only a battered shrub growing in the company of Podocarpus nivalis and Lepidothamnus laxifolius.

Remarks

See Also

Search for information on this species at the New Zealand Plant Conservation Network.

Paleobotany of Australia and New Zealand conifers.