Species
Ophioglossum petiolatum
Etymology
Ophioglossum: snake's tongue; from the Greek ophis and glossa; appearance of the fertile leaf
Common Name(s)
Stalked adder’s tongue fern
Threat Status
Nationally Critical
Status 2004
Nationally Endangered
Authority
Ophioglossum petiolatum Hook.
Qualifiers
RF, SO, Sp
Family
Ophioglossaceae
Flora Category
Vascular - Native
Synonyms
Ophioglossum pedunculosum sensu Allan (1961), O. reticulatum L.
Distribution
Indigenous. Known from the Three Kings (Great (Manawa Tawhi) Island), North, South and the Chatham Islands. Not recently recorded from the South Island. Last recorded from Chatham (Rekohu) Island in 2007. Still present on Great (Manawa Tawhi) Island, and locally from Te Paki to Kawhia and Arohaki Lagoon. Probably now extinct at Hokio, near Levin. New Zealand plants appear to belong to a widespread and common tropical species which reaches its southern limits in this country.
Habitat
Recorded from coastal and lowland habitats. A seasonally dormant species of ephemeral wetlands, moist talus and grassy areas, sandy margins of coastal lagoons, herbfields near lake margins, swamps and streams, and damp hollows within podocarp forest. Plants are most conspicuous between spring and late summer, dying down in autumn and winter.
Features
Perennial, seasonally dormant, firmly fleshy plants forming extensive patches in ideal conditions. Rhizomes erect, glabrous, loosely covered in fleshy white to pale yellow sheaths. Roots fleshy, proliferous. Sterile blade on short stalk up to 30 mm long, yellow-green to dark green. Lamina of sterile blade 15-150 x 6-40 mm, yellow-green to dark green, broadly to narrowly ovate, elliptic, undivided, base truncate to slightly attenuate, venation usually darker than rest of lamina, distinctly reticulate. Fertile spike on stalk 40-200 mm long. Fertile spike 14-60 mm long, bearing 15-48 pairs of sequentially ripening, long-persistent sporangia.
Similar Taxa
Ophioglossum coriaceum A.Cunn. which is generally smaller and has a narrower, oval-shaped and stalk-less sterile blade. The fertile spike is much shorter and carries fewer (7–15) pairs of spore-bearing capsules. However the distinction is not quite as clear cut and some populations with the sterile blade form of O. coriaceum but sporangia pairs of up to 25 are known. Further work on the status of plants referred to O. petiolatum in New Zealand is needed (see comments by de Lange & Rolfe 2010).
Flowering
October - December
Main Flower Colour
No Flowers
Fruiting
November - January
Propagation Technique
Easily grown by the division of whole plants. Does best in a fertile soil kept permanently moist (but not saturated). Will tolerate full sun but does better in semi-shade. Intolerant of competition from taller faster growing plants and very vulnerable to slug and snail browsing. This species makes an interesting and unusual pot plant. So far most New Zealand plants that have been investigated in detail have proved sterile. The sterility of the plants examined brings into question the exact status of plants attributed to this species in New Zealand.
Threats
May be overwhelmed by other plants or pigs. Destruction of suitable habitat or taking over of habitat by adventive species more able to tolerate changing nutrient status or with greater competitive ability. In cultivation this species is devastated by exotic snails and slugs and this maybe one of the problems for the species in the wild. Plants from two populations (Opuatia and Hokio) proved to be sterile.
Chromosome No.
Meiosis irregular
Endemic Taxon
No
Endemic Genus
No
Endemic Family
No
Where To Buy
Can be purchased from Oratia Native Plant Nurseries (info@oratianatives.co.nz).
Fact Sheet Prepared for NZPCN by:
P.J. de Lange 2004 (Updated 21 March 2011). Description based on de Lange et al. (2010).
References and further reading
Brownsey, P.J. 1985. Ophioglossum petiolatum at Hokio beach. Wellington Botanical Society Bulletin, 42: 33-34
Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand Ferns and Allied Plants. Auckland, David Bateman
Chinnock, R.J. 1998: Ophioglossaceae. Flora of Australia 48: 99-109.
de Lange, P.J. 1988. Ophioglossum petiolatum Hook in a reserve near Kawhia. Wellington Botanical Society Bulletin, 44: 4-7
de Lange, P.J.; Heenan, P.B.; Norton, D.A.; Rolfe, J.R.; Sawyer, J.W.D. 2010: Threatened Plants of New Zealand, Christchurch, Canterbury University Press. 471pp.
de Lange, P.J.; Rolfe, J.R. 2010: New Zealand Indigenous Vascular Plant Checklist. Wellington, New Zealand Plant Conservation Network. 164pp.
This page last updated on 3 Feb 2013