- Name also: True Oxlip
- Family: Primrose Family – Primulaceae
- Growing form: Perennial herb. Rootstock short, erect–oblique, many-rooted.
- Height: 10–30 cm (4–12 in.). Stalk leafless, hairy scape.
- Flower: Corolla regular, funnel-shaped, pale yellow, 15–25 mm (0.6–1 in.) wide, fused, narrow-tubed, 5-lobed, lobes notched. Calyx cylindrical–narrowly bell-shaped, bristly, lobe edges green, between lobes yellowish, lobes long, tapering. Stamens 5. Gynoecium fused, single-styled. Inflorescence a dense, one-sided, 10–30-flowered umbel.
- Leaves: In basal rosette; stalk shorter than blade, winged. Blade base usually elliptic, tapered or quite round, with rounded tips, margin irregularly and sharply dentate, hairy.
- Fruit: Cylindrical, 5-valved, 11–15 mm (0.4–0.6 in.) long capsule.
- Habitat: Yards, parks, banks. Also ornamental.
- Flowering time: May–June.
Primroses are good examples of a flower’s heterostyle. The stamens’ anthers and stigma in the most common Finnish primroses are never on the same level in the corolla mouth. The flower either has short stamens in the middle of the corolla tube and a long stigma in the corolla mouth, or long stamens in the mouth and a short stigma in the middle of the tube. The point of this arrangement is to ensure cross-pollination: long-stamened plants’ pollen doesn’t end up on the flower’s own stigma, but rather travels on a pollinator to a long-styled plant’s gynoecium and vice versa.
Oxlip is one of the first flowers to bloom in the spring. The genus’s scientific name is based on the Latin word primus, which means ‘first’ and refers to the early flowering time of the best-known species. The species is common as a feral plant in Southern Scandinavia, and its beauty has also brought it to Finnish gardens, from where it sometimes escapes to the wild.
Although oxlip can be easily confused with cowslip (P. veris), its calyx is green-edged and tighter than cowslip’s rather loose, entirely yellow collar. Another identification marker is the shape of the leaves: cowslip leaf blades are widest at the base, while oxlip blades are widest in the middle.