Chatham Island Mingimingi
Botanical name: Leptecophylla robusta
Synonyms: Cyathodes robusta, Cyathodes acerosa var. latifolia, Styphelia robusta
Common name(s): Chatham Island mingimingi, Pouteretere
About:
Leptecophylla robusta is a large, robust endemic shrub or small tree confined to the Chatham Islands. It is closely related to prickly mingimingi (Leptecophylla juniperina) but is generally much taller and stouter, with broader leaves, blunter tips and more numerous veins on the pale undersides.
Plants can reach several metres tall and may become an important component of coastal and inland scrub, forest and bog vegetation. In some parts of the southern Chatham Island tablelands it can even contribute to the forest canopy.
The species produces small fragrant cream to white flowers and attractive fleshy fruit ranging from red and pink to white.
Natural habitat:
Coastal and inland forest, scrub and restiad bog.
It occurs from exposed coastal vegetation through to sheltered inland forest and wetland environments.
On the southern tablelands it can become sufficiently large and abundant to form part of the forest canopy.
It is uncommon on sand and generally avoids active dune systems.
Growing environment:
Full Sun, Partial Shade, Wind, Coastal Exposure, Wet Soil, Bog Conditions, Cool Climate & Poor Soil tolerant.
The species is adapted to the cool, oceanic climate of the Chatham Islands and can tolerate exposed coastal conditions as well as wet inland sites.
It has a FACW wetland indicator rating, meaning it usually behaves as a hydrophyte but can also occur in non-wetland habitats.
Like other Leptecophylla species, it is sensitive to root disturbance.
Endemic distribution:
Endemic to the Chatham Islands.
Known naturally from Rēkohu/Chatham Island and Rangihaute/Pitt Island.
It does not naturally occur on mainland New Zealand.
Height:
Usually approximately 2–5 m tall.
Well-developed plants may reach around 8 m and occasionally form small trees.
Width:
Approximately 2–5 m across in mature shrubs or small trees, depending on exposure and habitat.
Flowering:
August–October.
Flowers are small, cream to white, fragrant and borne singly in the leaf axils or at the ends of branchlets.
Fruiting:
Fruit may occur throughout the year.
The fleshy drupes mature red, pink or white and are approximately 5–8 mm high and 6–10 mm wide.
Uses:
• Chatham Islands ecological restoration
• Native forest restoration
• Wetland and bog restoration
• Coastal revegetation
• Wildlife planting
• Specialist native plant collections
• Chatham Islands-themed gardens
• Native berry gardens
• Large shrub and small-tree planting
• Conservation collections
Appearance:
Growth habit:
A robust dioecious shrub or small tree, generally much larger and heavier in build than Leptecophylla juniperina.
Plants develop dense branching and may form substantial shrubs or, in favourable forest conditions, small trees.
The foliage is stiff and leathery, with leaves held erect or spreading from the branchlets.
Trunk/Bark:
Older stems and trunks develop firm dark grey to grey-brown bark.
The bark is fibrous, somewhat tessellated and often deeply furrowed.
Main stems are generally grey or grey-brown.
Young branchlets are yellow-brown, orange-brown or brown and are covered in fine hairs.
Leaf buds are conspicuous and initially clothed in silky white hairs before becoming more or less hairless.
Leaves:
Leaves are leathery, rigid and generally broader than those of Leptecophylla juniperina.
They are approximately 10–16 mm long and 2.2–3.4 mm wide in typical modern descriptions, although broader and larger leaves up to around 20 × 7 mm have also been recorded.
Shape ranges from ovate to oblong or narrow-lanceolate.
Upper surfaces are dark green, purple-green or bronze-green.
Lower surfaces are pale green to cream and marked with 6–8 conspicuous longitudinal veins, sometimes more.
The apex is blunt to broadly pointed and ends in a short callous tip rather than the long pungent spine characteristic of L. juniperina.
Margins are slightly recurved.
Flowers:
Flowers are small, sickly-sweet scented and borne singly in leaf axils or terminally.
Male flowers are carried on pedicels approximately 3.1–4.1 mm long, while female pedicels are around 2.4–3.2 mm.
Flowers are surrounded by numerous overlapping bracteoles.
The corolla is white to cream and bell-shaped.
The tube is approximately 1.7–2 mm long and usually about equal in length to the calyx.
The lobes are approximately 1.7–2.1 mm long and broadly acute.
Male flowers contain five stamens, usually enclosed within the corolla.
Female flowers contain a spherical ovary divided into four or five chambers.
Fruit:
The fruit is a fleshy, spherical drupe approximately 5–8 mm long and 6–10 mm wide.
Fruit colour varies from red and pink to white.
The internal stone is broadly transversely elliptic and approximately 2.8–4.3 mm long by 3.5–5 mm wide.
Its surface carries around 20 faint longitudinal ridges.
Seeds:
Seeds are contained within the hard endocarp.
The stone is internally divided into two to five chambers, and as many as five may contain developed seeds.
The fleshy fruit is suited to dispersal by fruit-eating birds and other animals.
Ecology:
Leptecophylla robusta is an important component of Chatham Islands shrubland, forest and wetland vegetation.
Its ability to occur from coastal scrub through to restiad bogs and forest demonstrates considerable ecological flexibility.
In some localities it becomes a dominant tall shrub or small tree and contributes directly to canopy structure.
The fleshy fruit provides food for native frugivores, while the dense branching provides shelter and habitat for smaller animals.
The species is naturally uncommon in a national context because of its restricted island distribution, but it can be locally abundant on the main Chatham Islands.
Its main threats are habitat clearance and local cutting for firewood.
It is relatively unpalatable to livestock and can therefore sometimes persist in rough pasture and partially modified vegetation.
Associated habitats:
Chatham Islands coastal scrub, lowland forest, inland shrubland, restiad bog, wetland margins, forest edges, tableland forest and rough pasture remnants.
It may occur alongside other characteristic Chatham Islands trees, shrubs, sedges, rushes, ferns and bog species.
How to grow:
Chatham Island mingimingi is best grown in cool, moist conditions with good airflow.
Choose a permanent planting position in full sun to partial shade with moist, humus-rich or peaty soil.
It can tolerate wetter ground than many native shrubs and is suitable for bog margins and damp sites.
Avoid hot, dry positions.
Root disturbance should be minimised at all stages. Plants are prone to sudden collapse if roots are damaged or repeatedly disturbed.
Container-grown plants should therefore be moved carefully and planted with the root ball kept intact.
Propagation:
Propagation is difficult.
Seed will germinate, but germination can be extremely slow and may take approximately 2–6 years.
Cuttings can be struck, though rooting is also slow.
The species has historically been established from transplanted wild plants, but this is unreliable and should not be used as a horticultural method.
Wild plants should not be removed.
Once propagation succeeds, seedlings and rooted cuttings should be disturbed as little as possible.
Cultural use:
The name pouteretere is associated specifically with this Chatham Islands species.
Detailed traditional Moriori and Māori material uses are not widely documented.
The plant nevertheless has strong regional significance as one of the distinctive endemic woody species of the Chatham Islands.
Garden value:
A highly distinctive native shrub or small tree for specialist collections, wetland gardens and Chatham Islands restoration planting.
Its robust habit, leathery foliage, pale-veined leaf undersides and colourful red, pink or white fruit provide strong ornamental interest.
It is particularly suitable for cool, moist gardens where its natural island climate can be approximated.
Because it is slow to propagate and sensitive to root disturbance, it is best regarded as a specialist conservation and botanical plant rather than an easy general-purpose garden shrub.