Ferns, Horsetails

Asplenium trichomanes (up to 20 cm) Maidenhair spleenwort Small fern with narrow oval leaves (5-20 cm) in leaflets. Blackish stalks and midribs. Ripe spores are present from September to October. Found on walls and rocks. Widespread but commonest in the West of the UK. Image taken at St Davids, Pembrokeshire .

Asplenium marinum (up to 20 cm) Sea spleenwort Small fern with tufted leathery shiny green leaves (15-20 cm). Midrib is green. Ripe spores are present all year except from mid-July to mid-August. Found on cliffs, caves, rocks ad walls exposed to the spray of the sea. Image taken at Marloes, Pembrokeshire .

Phyllites scolopendrium (up to 60 cm) Hartstongue Distinctive evergreen 'strap-shaped' leaves (10-60 cm). Spore cases are present on the underside of the leaves in diagonal strips, becoming ripe in August to March. Found on rocks, walls, woods and hedge banks. Widepsread and common, especially in the West. Image taken at Fontmell Down, Fontmell Magna, Dorset .

Polypodium vulgare (up to ???? cm) Common polyplody Blunt leaflets equal in length. Ripe spores are present from August to March. Found in woodland, on walls or rocks and even trees. Widespread and common, particularly in the West of the UK. Image taken at St Davids, Pembrokeshire, .

Dryopteris filix-mas (up to 130 cm) Male fern Medium fern. New leaves appear in April with pinnate leaflets. The secondary lobes are flat, toothed and blunt. Ripe spores are found near the mid-rib from August to November. Found in woodland, hedgerows, rocks and scree. Widespread and common. Image taken at Warton Crag, Silverdale, Lancashire .

Pteridium aquilinum (up to 400 cm) Bracken Stems form a creeping rootstock. Leaves appear as a 'shepherds crook' and are present from April to October. The ripe spores are found from August to October. Found in open woodland, dry heaths and moors. Common and widespread. Image taken at Jack Scout, Silverdale, Lancashire .

Equisetum fluviatile (up to 150 cm) Water horsetail Can grow in water. Yellowish-green stems are present from May to September with little or now branches. Green sheaths with short, black teeth that have pale edges. Blunt cones that are ripe in June. Image taken at Hordle Cliff, Milford-on-Sea, Hampshire .

Ferns are instantly recognised by the structure of their leaves (fronds) that are coiled when young. On the undersides of the fronds are the characteristic spore sacs known as sori. These are asexual structures; the spores fall onto the ground and develop into a heart-shaped structure called a prothallus (5 mm) that contain both male and female reproductive structures. On a film of water the male cells migrate to the female receptacle promoting the growth of a new fern structure from the prothallus after fertilisation. The structure, size and shape of the sori is the best aid for identification.

Horsetails are an ancient group of plants remaining relatively unchanged for millions of years. Leafless, non-flowering plants with hollow stems with many joints. The joints are covered with toothed sheaths and bear whorls of branches. They produce spores in club-like structures called cones at the tip of the stem. The spores develop underground into a prothallus that generates a new horsetail similar to a fern prothallus.

Botrychium lunaria (up to 30 cm) Moonwort Unstalked, oblong leaves with fan-shaped leaflets (3-9 pairs) present from May to August. Spores present in a two-pinnate spike from June to August. Found in grassy places including dunes and rocky ledges. Widespread. Image taken at Honister Pass, Lake District, Cumbria .

Cystopteris fragilis (up to 45 cm) Brittle bladder fern Delicate lanceolate leaves (5-45 cm) present from April to November. Black spores are present in whitish case from June to September. Found on rocks, walls on limestone soil. Widespread in the North and North-West of the UK. Image taken at Honister Pass, Lake District, Cumbria .

Equisetum arvense (up to 80 cm) Field horsetail Commonest horsetail, that hybridises with Water Horsetail. Medium green sterile stems that form patches. Green sheaths with spreading green green teeth and several whorls of thick green branches. Pinkish white fertile stems occur from April to May and are unbranched. Common and widespread. Image taken at Prestatyn, Denbighshire .