kahikātoa, mānuka, tea tree
NZ Myrtaceae Key - Online edition
Leptospermum scoparium J.R.Forst. & G.Forst. agg.
Indigenous to New Zealand. In the current sense this species is also shared with Australia, particularly Tasmania. However, there is evidence that mānuka in the strict sense is endemic to New Zealand. Further study is needed.
Leptospermum scoparium var. scoparium occurs throughout New Zealand from coastal to low alpine habitats. Leptospermum scoparium var. incanum Cockayne is confined to the north of the North Island.
Bark grey, dark graphite-grey or reddish, peeling in papery flakes with reddish undersides. Young branchlets and stems hairy, becoming hairless with age.
Adult leaves alternate, linear, narrowly elliptic or lanceolate to oblanceolate or obovate, 5–20 mm long, 1–8 mm wide, prickly to grasp, pale to dark green, leaf blade flat, leaf surfaces not puckered, hairy at first, becoming hairless, margins entire or finely scalloped, tips acute and mostly extending into a long stiff, prickly point; leaf stalks very short (sometimes appearing absent).
By the casual observer, mānuka (L. scoparium) is frequently confused with kānuka (Kunzea spp.), from which it can be easily distinguished by the hard, persistent, nut-like fruits, with non-persistent sepals, sharp-tipped leaves, and flowers which appear to be solitary.
In the context of this key, L. scoparium looks most similar to L. polygalifolium in terms of leaf length but leaves of the former are stiff and sharp-pointed, with rough leaf margins whereas leaves of the latter are slightly lemon-scented, less stiff, less sharply pointed, sometimes recurved. They also differ in that the former possess smaller fruit (5–8 mm wide) with valves each ± 2 mm wide and the latter possess larger fruit (± 6–10 mm wide) with valves each ± 4–5 mm wide; typical flowers of L. scoparium are white or pinkish and red-centred but those of L. polygalifolium are greenish to creamy white.
New Zealand L. scoparium is a very variable species. Currently there are two varieties accepted. The description above mainly applies to L. scoparium var. scoparium. Leptospermum scoparium var. incanum Cockayne is characterised by young branches, juvenile leaves and flower buds clad in long silky, grey hairs as well as pink-white or pink flowers.
Leptospermum scoparium is susceptible to myrtle rust (caused by Austropuccinia psidii). Leptospermum scoparium var. scoparium was given a conservation status of At Risk – Declining and L. scoparium var. incanum has a conservation status of Threatened – Nationally Vulnerable in 2018.
Leptospermum is a genus of about 87 species, mostly Australian, but extending to Malesia and New Zealand.
- CitSciHub
- Flora of New Zealand Online (L. scoparium var. incanum)
- Flora of New Zealand Online (L. scoparium var. scoparium)
- GBIF
- iNaturalist NZ (L. scoparium var. incanum)
- iNaturalist NZ (L. scoparium var. scoparium)
- NZPCN (L. scoparium var. incanum)
- NZPCN (L. scoparium var. scoparium)
- PlantNET: New South Wales Flora Online
- Plants of South Eastern New South Wales