akatea, large white rātā, Northland white rātā
NZ Myrtaceae Key - Online edition
Metrosideros albiflora Sol. ex Gaertn.
New Zealand endemic.
Uncommon in cultivation due to difficulties in propagation. Metrosideros albiflora is sensitive to cold and this limits its use as a garden plant across New Zealand. Occasionally available from specialist plant nurseries.
A sparsely distributed species of coastal to montane kauri (Agathis australis) forest in the northern North Island. Within this area it is most common south of Kaitaia (it is not known north of there) in central and western Northland, on Aotea / Great Barrier Island and the Coromandel Peninsula. Otherwise known from scattered locations in the northern Kaimai Range and northern Waikato. Apparently absent from the Auckland Region.
Stout climber up to ± 20 m when supported, or less commonly as a semi-climbing shrub.
Bark initially brown, grey with age, may be fragmented into small thick flakes. Branchlets round, hairy at first, becoming hairless with age.
Adult leaves arranged in opposite pairs, each pair being at right angles to the pair below, leathery, ovate to elliptic to broadly lanceolate, 35–90 mm long, 20–35(–46) mm wide, upper surface darkish green, usually glossy, lower surface paler, leaf surface flat, upper and lower surfaces hairless, oil glands not readily visible to the naked eye, but easier to see on the lower surface; margins entire, tips abruptly pointed, leaf stalks 2–6 mm long, stout, hairy.
Flowers in grape-like bunches of 6–10, borne terminally or axillary, flowers ± 6–7 mm in diam., flower stalks ± 3–5 mm long, petals 5, white, orbicular, ± 5 × 5 mm; sepals 5, tips free, persistent, hairless (apart from hairy sepal margins); stamens white, filaments 15–30 mm long, much longer than petals. Main flowering period: late winter to spring.
Distinguishable from the other white-flowered Metrosideros vine species (M. colensoi, M. diffusa and M. perforata) by the much larger adult leaves, ≥ 35 mm long and by the stamen filaments 15–30 mm long as opposed to leaves <25 mm long and stamen filaments ± 10 mm long. The juvenile foliage of M. albiflora could be confused with M. carminea and M. perforata. Like M. carminea the leaves are softly hairy but the emergent leaves are pale to dark green never flushed pink; like M. perforata the leaf surfaces are prominently gland spotted but the leaves of M. perforata are hairless and leathery, those of M. albiflora are soft and hairy.
Metrosideros albiflora is believed susceptible to myrtle rust (caused by Austropuccinia psidii) so it has received a precautionary threat assessment of Threatened – Nationally Vulnerable.
Metrosideros is a genus of more than 50 species of trees, shrubs and vines, mostly found in the Pacific region. New Zealand is well represented by having 12 endemic species.