- Name also: English Plantain, Narrowleaf Plantain (USA)
- Family: Plantain Family – Plantaginaceae
- Growing form: Perennial herb.
- Height: 10–50 cm (4–20 in.). Stem leafless, with arching base–straight, clearly 5-edged, varyingly hairy scape.
- Flower: Corolla regular (actinomorphic), brownish, small, approx. 2–3 mm (0.08–0.12) wide, fused, 4-lobed; lobes quite sharp, membraneous, 1.5–2.5 mm (0.06–1 in.) long. Calyx 4-lobed. Stamens 4, filaments long, anthers yellowish white. Pistil fused, a single carpel. Carpels mature before stamens (protogynous). Inflorescence a very dense, globose–egg-shaped (sometimes long cylindrical) spike.
- Leaves: In basal rosette, stalked, quite erect. Blade lanceolate–almost linear, with margins entire–sparsely toothed, sparsely haired, parallel-veined.
- Fruit: Brown, 3–4 mm (0.12–0.16 in.) long capsule, opening like the lid of a box.
- Habitat: Meadows, dry meadows, grazing land, lawns, banks, waste ground, beside railway tracks, harbours.
- Flowering time: (May–)June–August.
The appearance of ribwort plantain stands in Finland varies to a certain extent. Those that arrived in south-western Finland in ancient times are short-spiked, while new arrivals growing much further north are characterised by long spikes. Its flowers are vestigial and very modest. Most of the colour is added to the inflorescence by the anthers, which push against the long, thin filaments in the wind, making them shake and shed their pollen. The protruding stigmas capture the bits of pollen as they float on the wind. Due to the randomness of wind-borne pollination the plants make a large amount of pollen. Most of it goes to waste, and some ends up e.g. in the water and then in the mud at the bottom of the lake. A tiny piece of highly durable pollen can last up to a thousand years, and thus have a story to tell researchers about the ancient flora in the area.
Based on pollen that has been discovered, ribwort plantain spread to Finland in the Stone Age when agriculture was in its infancy. It is only common to any extent on the Åland Islands, the Turku archipelago, the south-western Finnish coast and the south-east around Parikkala, and there are individual and often temporary stands further north too. The species has greatly exploited human activity and traditionally grown in dry grazing meadows. Its dry scape and strongly-veined leaves do not particularly appeal to cattle, so ribwort plantain is often left to grow in peace. The persistent scapes also thrive on tended lawns: the lawn-mower might cut the tip of the leaves off but the scapes usually bend down and bounce back up when the danger has passed.
Ribwort plantain’s leaves can be almost linearly hay-like, but they are most commonly lanceolate. Its Finnish name was probably intended to emphasise the way the form of its leaves differs from its close relative hoary plantain (P. media). Usually the easiest way to differentiate between different plantains is according to identification markers on the leaves, and in difficult cases ribwort plantain can also be identified by its clearly bristly scapes and its yellow anthers.