- Name also: Bluebur, Bristly Sheepbur, European Stickseed, Spiny Stickseed, Two-row stickseed
- Family: Borage Family – Boraginaceae
- Growing form: Annual herb.
- Height: 20–60 cm (8–24 in.). Stem erect, branching near the top. Dense, greyish fur.
- Flower: Corolla regular (actinomorphic), 2–4 mm (0.08–0.16 in.) wide, pale blue, fused, funnel-shaped, 5-lobed. Corolla mouth with 5 shallow protuberances. Calyx fused, 5-lobed almost to base. Calyx lobes spreading in fruiting stage, 4–6 mm (0.16–0.24 in.) long. Stamens 5. Gynoecium fused, single-styled. Inflorescence a scorpioid cyme. All flowers with subtending bracts.
- Leaves: Alternate, stalkless. Blade lanceolate to elliptic.
- Fruit: 4-part schizocarp. Mericarps 4–6 mm (0.16–0.24 in.) long (without spines), edged with 2–3 rows of broad-based barbed spines. Fruit-stalk shorter than calyx, erect.
- Habitat: Ruins, old barracks, railway stations, wasteland.
- Flowering time: June–August.
Bur forget-me-nots (stickseeds) look quite similar to forget-me-nots, but the easiest way to differentiate between them is by examining the carpels: forget-me-not carpels are smooth, but stickseed carpels are edged by 1–3 rows of usually hook-tipped hairs. While forget-me-nots tempt ants to spread their seeds by means of the juicy food attached, stickseed carpels in their natural environment mainly attach themselves to animal fur.
Bur forget-me-not has travelled to Finland from its original habitats in Eurasia with domestic animals, people, and especially grain. Typical habitats are different kinds of dry, sandy places close to human activity. The species has established itself in Finland around old barracks and ramparts. Bur forget-me-not grows sporadically in Finland however: it has arrived with foreign grains in our harbours, railway yards and mills, and in many garrison areas with soldiers’ provisions and their horses’ oats. The main entry route in times of both war and peace has been from the east. Bur forget-me-not arrived in Finland a long time ago already, mainly during the period when Finland was under Russian influence.
The best way to distinguish between deflexed bur forget-me-not (L. deflexa), which is native to Finland, and bur forget-me-not is to examine the fruits: on the former they droop down further than the calyx on the flower-stalk, while the flower-stalk on the latter is erect and shorter than the calyx. Bur forget-me-not, which has a faintly disagreeable smell, is also one of the rare fragrant members of the Borage family. The area that it has been found in can also often provide a clue: deflexed bur forget-me-not favours natural rock and fellsides, while Bur forget-me-not grows almost exclusively close to human activity.