Prumnopitys taxifolia is a species of
dioecious evergreen
conifer in the family
Podocarpaceae, reaching heights of tall, with a
trunk of up to in diameter. Branches are initially ascending and eventually become spreading, forming a domed or rounded
crown. The
bark is thin and smooth (particularly on younger trees); it has spots, similar to hammer marks, which are red or purplish-brown in colour when fresh, weathering into a dark brown to black colour, and peeling freely into thick flakes. The outer bark itself can vary in colour from a dark brown to an almost black colour. The wood is very dense, hard, and a dark brown to a yellow-brown colour.
P. taxifolia has an average lifespan of 600 years, although a specimen from
Tongariro National Park is estimated to have lived for more than 1000 years.
Prumnopitys taxifolias young form is distinct and the species profoundly exhibits
heteroblasty (a significant change in a plant's form). Its young form, resembles a tangled
shrub, is so distinct that the first botanists in New Zealand initially thought they were separate species. Unlike the related
miro (
Pectinopitys ferruginea),
P. taxifolia has a distinctive and long-lasting young stage, which is a tangle of slender, flexible, divaricating
branchlets that are interspersed with a scattering of leaves. After several decades, the adult tree begins to grow out of the top of the young shrub and the divaricating branchlets will drop off. It is unknown why this species developed this characteristic; one possibility is that the tangled branches are designed to create a warm temperature inside the shrub, hence the species could survive in colder climates, or it may serve as a defence against browsing animals. The young stage can last for up to 60 years. Young
leaves are 5–10 × 1–2 mm long and brown to pale yellow in colour, narrow and tapering, with a pointed tip, and they can have long whip-like
shoots. Adult leaves are 10–15 × 1–2 mm long, dark green in colour,
glaucous,
subdistichous and often
apiculate in character. They generally have a broad shape, but can be more
pectinate in character, and are (6–)10–20 mm long, (1–)1.5–2 mm wide. Leaves are widest near the middle, with nearly parallel sides. The
midrib is raised on a bluish-green surface, where there are waxy, pale bluish-green bands of
stomata. The Canadian botanist,
James Emory Eckenwalder, hypothesised that the leaves of
P. taxifolia potentially contain unidentified physiologically active
compounds. Like all conifers,
P. taxifolia does not produce flowers or true fruits, but instead produces pollen and seed in
cones, or 'pseudo-fruits'. The species is dioecious, with male and female reproductive structures on separate trees. The
ovules are found on short axillary branches, with 3–10 per a 40 mm long spike.
P. taxifolias male pollen cones are found on nearly leafless lateral and axillary spikes near the ends of foliage branches. Each spike is yellow in colour, and can have up to 10–30 cones per spike, each 5–12 mm long and approximately 2 mm wide. The seed cones take 12–18 months to mature and are found throughout the year. They are round to oval in shape, fleshy, globe-shaped or nearly spherical, purplish-black in colour, and about 8–10 mm wide.
P. taxifolia has a
diploid chromosome count of 38.
Phytochemistry The
sap of
P. taxifolia contains
matairesinol, a compound which has been investigated in cancer research. In addition to matairesinol, the
heartwood of the tree contains numerous other compounds, which includes, but is not limited to
aromadendrin,
kaempferol,
quercetin, and
genistein. Foliage oils of the tree were investigated in 1987 in the scientific journal
Phytochemistry. Researchers found seven
sesquiterpene hydrocarbons and two oxygenated sesquiterpenes, ten
diterpene hydrocarbons, and two oxygenated diterpenes (including
ferruginol) were identified. ==Gallery==