Frond fern with asymmetrical, dark green, and shiny segments on the upper surface and pale green on the underside.
Scientific name: Cyrtomium falcatum (L. Fil.) C. Presl
Common name: Japanese holly fern; Asian net-veined holly fern; house holly fern; Japanese netvein holly fern
Status in Portugal: Invasive species in the Azores and on Madeira but no records outside cultivation in mainland Portugal.
Risk Assessment Score: [in development].
Synonymy: Polystichum falcatum (L. f.) Diels in Engl. & Prantl
Last update: 28/11/2016 ! Profile prepared by the LIFE+ Terras do Priolo project team.
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How to recognize it
Herbaceous, perennial fern, with an erect rhizome and ovate, 2 cm, brown scales..
“Leaves”: stem base with two types of scales: one dark and small and the other large, pale and scaly; fronds up to 5 meters with a blade 2 to 3 penatissecta at the base, green or light green above, pale below; rachis with dark brown obtuse tubercles; 1st order segments measuring 65 x 26 cm; 2nd order segments with acuminate apices. The fall of the stipes causes oval scars on the stem.
“Flowers/ Fruits”: orbicularis sori; ellipsoidal spores.
Cyrtomium falcatum can be confused with some larger forms of Cyrtomium fortunei in herbarium, although it is easy to distinguish when alive due to the shiny surface of the fronds of C. falcatum.
Characteristics that aid invasion
Reproduction is sexual, producing thousands of spores/plant/year.
Native distribution area
South Africa, China, India, Southeastern Asia and Polinesia.
Distribution in Portugal
Invasive in the Azores (all islands) and on Madeira (Madeira island).
For more detailed locations of this species, check the online interactive map. This map is still incomplete – we need your help! Contribute by submitting records of the location of the species where you can find it.
Other places where the species is invasive
Europa, North America, Hawaii, Australia, and New Zealand.
For ornamental purposes.
Preferential invasion environments
Coastal dunes (dune vegetation, coastal meadows), Festuca meadows, rocky shores, corded lava, cliffs, coastal scrubs, Erica scrubs, roadside walls and slopes, Pittosporum undulatum scrubs, very exposed dry places, ravines.
Although legally not considered invasive in Portugal, it shows invasive behaviour in some locations in the Azores and on Madeira.
Impacts on ecosystems
The species forms dense patches that disrupt the structure, abundance and succession of the ecosystems it invades. It prevents the development of native vegetation and reduces the diversity of species by competition; recruitment.
Potentially high costs in applying control measures.
Natura 2000 Network habitats more prone to impacts
– Vegetated sea cliffs with endemic flora of the macaronesian coasts (1250);
– Fixed coastal dunes with herbaceous vegetation ("grey dunes") (2130);
– Endemic Macaronesian heaths (4050).
Controlling an invasive species demands a well-planned management, which includes the determination of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention priorities, selecting the adequate control methodologies and their application. Afterwards it is fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as to perform, whenever necessary, the follow-up control.
The control methodologies used for Cyrtomium falcatum include:
New colonies are often the result of propagation of cultivated plants so efforts must be made to eliminate plants from adjacent areas which may require the cooperation of landowners in the vicinity.
Hand pulling: The control of C. falcatum is mainly done by manual pulling. Uprooted plants should be removed from the site to prevent the spread of spores.
Foliar application of herbicide: where dense populations of C. falcatum exist, or where plants occur on sensitive substrates such as historic masonry structures, herbicide can be applied (active ingredient: glyphosate).
Visit the webpage How to Control for additional and more detailed information about the correct application of these methodologies.
Silva L, Corvelo R, Moura M, Delgado OR, Fernandes FM (2008) Cyrtomium falcatum (L. fil.) C. Presl. In: Silva L, E Ojeda Land & JL Rodríguez Luengo (eds.) Flora e Fauna Invasora da Macaronésia. TOP 100 nos Açores, Madeira e Canárias, pp. 221-224. ARENA, Ponta Delgada.
Schäfer H (2005) Flora of the Azores. A Field Guide. Second Enlarged edition. Margraf Publishers, Weikersheim.