Pennantia baylisiana

Pennantia baylisiana is a shrubby, multi-trunked tree with a broad crown, unlike the three other species in the genus Pennantia. It does not have a divaricating juvenile form, unlike the other New Zealand Pennantia species kaikōmako (P. corymbosa). It grows to a height of 5 m in the wild, though has been recorded reaching 8 m in cultivation. It has pale greyish-brown bark and branchlets that are covered with lenticels. It has leathery, green, egg-shaped alternate leaves around 12–16 by 7–10 cm. Adult leaves have smooth margins but young leaves are toothed. The leaves are large and flat in shade-grown plants, up to 20 by 10 cm, but notably curled along their sides – almost rolled – on branchlets exposed to sun and wind. They have distinctive hair-covered domatia on the underside, at the junction of the midrib and secondary veins, and are suspended from 2.5 cm long petioles. Flowering occurs from October to November, producing 1.5 by 1.5 mm greenish-white flowers in panicles with 2.6 mm petals. Flowers usually arise on woody branches, though some are terminal. The stamen is made up of a 1–1.4 mm long anther on top of a 1.5 mm long filament, though the pollen is usually sterile. It has a 2.8 by 2 mm cylindrical ovary with a stigmatic ring 1.5–1.8 mm in diameter. Fruiting is from January through to April in cultivated plants yielding 10 by 4.5 mm ellipsoid fruit. …

It is only found in the wild on Manawatāwhi / Three Kings Islands, an island chain 55 kilometres (34 mi) north-west of the top of the North Island, on Great Island (Manawatāwhi). There is only one tree known in the wild; a female growing above a cliff on the northern face of Great Island. This tree has been called "the loneliest tree". The species has now been propagated by plantings in various garden locations in New Zealand, including Otari-Wilton's Bush, and around 200 saplings have been planted in Northland.