Pteris macilenta
Common name
sweet fern
Synonyms
Pteris pendula Colenso
Family
Pteridaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Ferns
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
PTEMAC
Chromosome number
2n = 116, 120
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | Not Threatened
Previous conservation statuses
2009 | Not Threatened
2004 | Not Threatened
Distribution
Endemic. New Zealand: North, South and Chatham Islands. Widespread in the North Island (except for the central volcanic plateau and adjacent main axial ranges), common in the northern part of the South Island reaching a western southern limit near Greymouth and in the east on Banks Peninsula where it may have been planted (Wilson 2009).
Habitat
Coastal to montane (in northern areas). Usually in dry, less heavily vegetated sites in forest but also on cliff faces and banks in light scrub. Especially common overlying calcareous or other base-rich rocks.
Features
Terrestrial ferns. Rhizomes short, erect, scaly. Stipes 0.1-0.5 m long, yellow-brown, base scaly. Laminae 0.25-0.9 × 0.15-0.5 m, light green, 3-pinnate, ovate, thin,; veins reticulated along midribs but free elsewhere, Pinnae widely spaced; most lower secondary pinnae stalked or sessile. Ultimate segments 5-15 × 3-5 mm, oblong, apices deeply toothed, margins almost smooth. Sori continuous along pinna margins on a marginal vein, protected by a membranous inrolled pinna margins.
Similar taxa
Pteris macilenta is most similar to P. saxatilis which is rather like a diminutive form of it. Pteris saxatilis differs from P. macilenta by the very widely spaced primary and secondary pinnae; laminae 0.15-0.5 × 0.12-0.25 m, and the ultimate segments up to 15 × 5 mm. Although Brownsey & Smith-Dodsworth (2000) state that intergrades exist between P. macilenta and both P. comans and P. saxatilis, this seems more likely to refer to hybrids between the latter two species as P. macilenta is genetically distinct from both P. comans and P. saxatilis and unable to hybridise with them (J.E. Braggins pers. comm.). The New Zealand form of Pteris comans differs from both P. macilenta and P. saxatilis by the coriaceous (leathery) fronds, reticulate venation, overlapping pinnae and large ultimate segments
Flowering
Not applicable - spore producing
Flower colours
No flowers
Fruiting
Not applicable - spore producing
Propagation technique
Easily grown from fresh spores and young plants transplant readily. Prefers semi-shade in garden settings, planted into a moist, rich free draining soil. Can be cold sensitive
Etymology
pteris: A fern known to the ancient Greeks; from the Greek pteris
Taxonomic Notes
The unpublished work of J.E. Braggins suggests that the name P. macilenta as applied by Allan (1961) and other authors is incorrect and that this name is actually the first legitimate name for the fern known as P. saxatilis. His work suggests that the correct name for the plant called here P. macilenta is in fact P. pendula Colenso. However, until such time as that research is published, and in line with other published works (e.g., Brownsey & Smith-Dodsworth 2000), the current usage of the names P. maclienta and P. saxatilis are retained.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (17 January 2012). Description adapted from Brownsey & Smith-Dodsworth (2000).
References and further reading
Allan, H.H. 1961: New Zealand Flora. Vol. I. Wellington, Government Printer.
Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand Ferns and Allied Plants. Auckland, David Bateman.
Wilson, H. 2009: Natural History of Banks Peninsula. Christchurch, Canterbury University Press.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Pteris macilenta Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/pteris-macilenta/ (Date website was queried)