SafePlants

Wall-rue (Asplenium ruta-muraria)

Wall-rue is a small fern often found in unexpected places, thriving on limestone rocks and in crevices of old walls.

Considerations for Pets

• This is a small, delicate plant.
• Wall-rue is often found growing on walls in urban areas.

Taxonomy and Nomenclature

• Scientific Name: Asplenium ruta-muraria
• Common Names: Wall-rue, Wall Rue Spleenwort, Stone Scale Fern
• Other Scientific Names: Asplenium cryptolepis, Amesium Ruta muraria
• Family: Aspleniaceae (Spleenwort Family)
• French Name: Doradille des murailles

Distribution and Habitat

• Wall-rue is commonly found across Britain, Ireland, and in parts of Europe and Asia, including Appalachia and New England.
• It thrives in the harsh environment of old mortar, rocks crevices, walls and bridges, particularly those made of limestone.
• In Northern Ireland, it's a common fern, even in urban areas.

Morphological Characteristics

• Wall-rue is a small, delicate, evergreen fern.
• Fronds are branched, ranging from 1.5 to 7 inches (4 to 17 cm) long.
• Frond length is up to 12cm.
• The fronds are triangular-ovate in outline and long stalked.
• Pinnae are no more than 5 on each side, with the lowest itself pinnate, having up to 5 segments.
• It has blueish-green or olive-green, club-shaped leaflets with toothed margins.
• It grows almost exclusively on vertical surfaces.

Quirky Facts

• Wall-rue is considered the smallest native fern in the UK.
• Some people believe these tiny plants can harm the walls they grow on.

Interactions with Other Organisms

• Wall-rue is sensitive to atmospheric pollution.

Further Information

• Collins English Dictionary
• American Heritage Dictionary of the English Language