The New Zealand Plant Conservation Network

Species

Sicyos mawhai

Common Name(s)

mawhai, ambush vine

Current Conservation Status

2012 - At Risk - Relict

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - At Risk - Relict
2004 - At Risk - Relict

Qualifiers

2012 - CD, RR
2009 - CD

Authority

Sicyos mawhai I.Telford et P.Sebastian

Family

Cucurbitaceae

Flora Category

Vascular - Native

Structural Class

Dicotyledonous Lianes and Related Trailing Plants

Synonyms

None - described in 2012

Distribution

Endemic. Kermadec Islands: (Heralds, Meyers, Raoul, Macauley, Haszard). New Zealand: Three Kings, North Island (formerly widespread in northern half) and northern offshore islands), South Island (formerly Marlborough Sounds). Now extinct in the South Island and probably extinct on the mainland of the North Island and on many near shore islands.

Habitat

Coastal species that has been collected from beach strands, including boulder beaches and banks, from coastal forest (especially forest margins), coastal shrubland and on offshore islands within sea-bird colonies.

Features

Herbaceous climber; stems annual, up to 14 m long, up to 2.5 mm diameter, sparsely hirsute with simple multicellular celled hairs and glandular hairs, glabrescent. Tendrils 3–5-branched. Leaves: petiole 25––135 mm long, minutely glandular hairy; lamina broadly ovate in outline, 45–135 × 60–165 mm wide, cordate with the basal sinus ± closed by overlapping lobes, acuminate, shallowly palmately 5- or 7-lobed, the lobes rounded–triangular, margins coarsely dentate with apiculate teeth. Male inflorescence a 14–35-flowered raceme 45–205 mm long; peduncle 35–125 mm long. Male flowers: pedicels 3.5–27 mm long; hypanthium broadly campanulate, 3.8–4.2 mm diameter; calyx lobes linear, c.1.2mm long; corolla rotate, 7–13 mm in diameter, 5-lobed, the lobes rounded–triangular, 2.0–3.5 mm long; disc c.2 mm diameter; staminal column 1.8–2.2 mm long; staminal head 1.9–2.4 mm diameter. Female inflorescence a 6–20-flowered head; peduncle 12–35mm long. Female flowers: subsessile; ovary ovate, 3.2–4.0 mm long, 2.0–2.6 diameter, echinulate with barbed aculei; hypanthium above the constriction broadly campanulate, c.2.4 mm diameter, abaxially scabridulous; calyx lobes linear, c.0.8 mm long; corolla 4–6.8 mm in diameter, glabrous abaxially and adaxially, glandular papillose on margins, white, 5-lobed; lobes triangular–ovate, 2.0–2.3 mm long; disc c.1.3 mm diameter; style c.1.8 mm long; stigma 2-branched, the branches recurved. Fruit ovate, 8.0–13.0 × 4.0–5.8 mm, obtuse or subacute, the surface glabrous or sparsely and minutely hairy, echinate; aculei dense, 2.2–3.6–6mm long, retrorsely barbed. Seeds ± ellipsoidal,5.6–6.0 × 3.8–4.5 mm, brown.

Similar Taxa

Sicyos mawhai could only be confused with S. australis. Sicyos australis differs from S. mawhai by the male flowers which are < 10 mm diameter; by the smaller, grey-green 3-5 acutely-lobed leaves; and broad, open leaf sinus. Both species of Sicyos have at times been confused with choko (Sechium edule), especially when in a vegetative state. However, choko has larger, darker green leaves, and the fruits of choko are unmistakable, being larger, pear-shaped, pale green, and unadorned with sharp spines.

Flowering

In suitable conditions flowers are produced throughout the year.

Fruiting

In suitable conditions fruits are produced throughout the year.

Propagation Technique

Easily grown from seed. However seed can take several months to germinate. Can become weedy but plants are prone to collapse as a result of attack by viruses (see Delmiglio & Pearson 2006).

Threats

Sicyos mawhai has vanished from much of its past range over the last 50 or so years (see comments by Cameron 1992). Currently it remains common only on the less accessible northern offshore islands (e.g., Three Kings, Poor Knights and Mokohinau Islands) and on the Kermadec Islands. Sicyos mawhai is susceptible to cucumber, watermelon and zucchini mosaic virus (Delmiglio & Pearson 2006) and this probably accounts for the sudden decline from the more modified parts of its range. Currently as there is no further evidence of decline and, being secure on the Kermadecs and some other island groups, this species, as S. aff. australis (a) (AK 252822; New Zealand) has been listed as "Relict" (de Lange et al. 2009).

Chromosome No.

2n = 26

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 29 Apr 2014