Myoporum laetum

Myoporum laetum
Leaves and fruit
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Asterids
Order:	Lamiales
Family:	Scrophulariaceae
Genus:	Myoporum
Species:	M. laetum
Binomial name
Myoporum laetum G. Forst.[1]
Synonyms[2]
Myoporum pubescens G. Forst. Citharexylum perfoliatum G. Forst. Myoporum crystallinum Hort. ex Kunze Myoporum laetum var. decumbens G.Simpson

Myoporum laetum, commonly known as ngaio /ˈnaɪ.oʊ/ or mousehole tree is a plant in the family Scrophulariaceae endemic to New Zealand, including the Chatham Islands. It is a fast growing shrub, readily distinguished from others in the genus by the transparent dots in the leaves which are visible when held to a light.

Description

Ngaio is a fast-growing evergreen shrub or small tree which sometimes grows to a height of 10 metres (30 ft) with a trunk up to 0.3 metres (1 ft) in diameter, or spreads to as much as 4 metres (10 ft). It often appears dome-shaped at first but as it gets older, distorts as branches break off. The bark on older specimens is thick, corky and furrowed. The leaves are lance-shaped, usually 52–125 millimetres (2–5 in) long, 15–30 millimetres (0.6–1 in) wide, have many translucent dots in the leaves and edges which have small serrations in approximately the outer half.^[2][3][4]

The flowers are white with purple spots and are borne in groups of 2 to 6 on stalks 7–15 millimetres (0.3–0.6 in) long. There are 5 egg-shaped, pointed sepals and 5 petals joined at their bases to form a bell-shaped tube 3.5–4.5 millimetres (0.1–0.2 in) long. The petal lobes are 4.5–5.5 millimetres (0.18–0.22 in) long making the flower diameter 15–20 millimetres (0.6–0.8 in). There are four stamens which extend slightly beyond the petal tube and the ovary is superior with 2 locules. Flowering occurs from mid-spring to mid-summer and is followed by the fruit which is a bright red drupe 6–9 millimetres (0.2–0.4 in) long.^[2][3][4]

Flower of Ngaio

Taxonomy and naming

Myoporum laetum was first formally described in 1786 by Georg Forster in Florulae Insularum Australium Prodromus.^[1][5] The specific epithet (laetum) is a Latin word meaning "happy".^[6]

Distribution and habitat

Ngaio grows very well in coastal areas of New Zealand including the Chatham Islands. It grows in lowland forest, sometimes in pure stands, others in association with other species such as nikau (Rhopalostylis sapida).^[2]

Ecology

Myoporum laetum has been introduced to several other countries including Portugal, South Africa and Namibia.^[2] It is considered an invasive exotic species by the California Exotic Pest Plant Council.^[7]

Uses

Indigenous use

The Māori would rub the leaves over their skin to repel mosquitoes and sandflies.^[8]

Horticulture

Ngaio is a hardy plant that will grow in most soils but needs full sun. It can also tolerate exposure to salt spray.^[9] It can be grown from seed or from semi-hard cuttings.^[3]

Toxicity

The leaves of this tree contain a liver toxin Ngaione^[10] which can cause sickness and or death in stock such as horses, cattle, sheep and pigs.

Māori legend

According to Māori legend,^[11] a Ngaio tree can be seen on the moon:

The man in the moon becomes, in Māori legend, a woman, one Rona by name. This lady, it seems, once had occasion to go by night for water to a stream. In her hand she carried an empty calabash. Stumbling in the dark over stones and the roots of trees she hurt her shoeless feet and began to abuse the moon, then hidden behind clouds, hurling at it some such epithet as "You old tattooed face, there!" But the moon-goddess heard, and reaching down caught up the insulting Rona, calabash and all, into the sky. In vain the frightened woman clutched, as she rose, the tops of a ngaio-tree. The roots gave way, and Rona with her calabash and her tree are placed in the front of the moon for ever, an awful warning to all who are tempted to mock at divinities in their haste.^[12]

References