Gymnocarpium robertianum

Tracheophyta PteropsidaWoodsiaceaeGymnocarpiumGymnocarpium robertianum


A deciduous fern of cracks, fissures and scree in limestone rock, but also found in shallow grikes of limestone pavement, and, rarely, on chalk. It prefers warm, sunny exposures but can tolerate light shading. It has become established as a garden escape on walls and culverts. Lowland to 585 m at Carreg yr Ogof (Carms.).



World Distribution

Circumpolar Boreo-temperate element, with a disjunct distribution.

© K.J. Walker, BSBI

Broad Habitats

Inland rock (quarries, cliffs, screes)

Light (Ellenberg): 7

Moisture (Ellenberg): 3

Reaction (Ellenberg): 8

Nitrogen (Ellenberg): 4

Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 2.7

July Mean Temperature (Celsius): 14.6

Annual Precipitation (mm): 1168

Height (cm): 45

Perennation - primary


Life Form - primary

Non-bulbous geophyte (rhizome, corm or tuber)



Clonality - primary

Rhizome far-creeping

Count of 10km squares in Great Britain: 113

Count of 10km squares in Ireland: 1

Count of 10km squares in the Channel Isles: 0

Atlas Change Index: -0.37

JNCC Designations


Scarce Atlas Account

Scarce Atlas Account: 

Gymnocarpium robertianum (Hoffm.) Newman

Limestone fern

Status: scarce



This fern is confined to calcium-rich substrates and usually grows on natural limestone screes and pavement. It is usually found on Carboniferous and oolitic limestone, but there is at least one locality on hard chalk. It is favoured by open sunny situations, although it may get established in shady grikes. G. robertianum is associated with other limestone species such as Asplenium viride, Cystopteris fragilis, Geranium robertianum, Mercurialis perennis, Oxalis acetosella and Phyllitis scolopendrium. It rarely grows above 450 metres altitude, but reaches 585 metres on Carreg yr Ogof in the Black Mountains.

This perennial species is easily grown from spores and is a favourite with fern gardeners. It often escapes and establishes itself on man-made walls and in culverts even in the drier and colder parts of the country.

In its natural habitats G. robertianum can be ousted by competition with Mercurialis perennis and hawthorn scrub, and limestone quarrying has taken its toll of its localities. 

This is a circumboreal species. In Europe it is most frequent in central Europe, extending south to the Pyrenees and north to northern Norway (Jalas & Suominen 1972).



A. C. Jermy

Atlas text references

Atlas (14d)
Curtis TGF, McGough HN
1988.  The Irish Red Data Book. 1. Vascular Plants.
Hultén E, Fries M
1986.  Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1972)
Bangerter EB, Cannon JFM, Jermy AC
1978.  Ferns and their allies. The Island of Mull: a survey of its flora and environment. :12.1-12.7.
Meusel H, Jäger E, Weinert E
1965.  Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
Page CN
1997.  The ferns of Britain and Ireland, edn 2.
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.