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Thale Cress
Arabidopsis thaliana
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Thale cress is a tiny, delicate annual with small white flowers and long, thin seed pods. It often grows on dry, sunny, human-made places such as rocks, sandy ground and walls, and is a common little weed in many regions. It is also famous as a key plant used in biology research.
Did you know?
- Thale cress was the first plant to have its whole genome sequenced.
- Scientists use it because it grows fast and makes many seeds.
About the species
Identification
Very small, 5–30 cm tall, bluish‑green and delicate. A low circle of smooth‑edged leaves sits at the base; the few stem leaves are also smooth‑edged and lack stalks. Stems one or several, often branched, hairy near the base. Flowers tiny with four white petals (2–4 mm). After flowering, many thin, straight pods 1–1.5 cm long spread out on short stalks along the stem. Not to confuse with shepherd’s‑purse, which has flat, heart‑shaped pods; thale cress pods are long and needle‑like. Flowers in Finland in May–June.
Plant group
Herbaceous plants
Habitat
rock
Flowering
May–Jun
About the habitat
Dry, sunny, open ground: rocky outcrops, sandy soil, grazed banks, dry grassland, old stone walls and piles, and coastal islets; also on disturbed ground such as fields, rail yards and harbours. Common and native in southern Finland; further north it is rarer and considered an old introduction.
Sources
Photo: guywallbanks, CC BY 4.0 https://www.gbif.org/occurrence/5938246932
Text: Pinkka: BIO-503 Suomen kasvisto ja kasvillisuus - Kulttuuriympäristöt: kedot, CC BY 4.0 https://laji.fi/taxon/MX.38366
Text: Pinkka: Kasvitieteen retkeily Ahvenanmaalle - Nåtön biologinen asema, CC BY 4.0 https://laji.fi/taxon/MX.38366
Text: Pinkka: A Pohjolan kasveja - Abies-Allium, CC BY 4.0 https://laji.fi/taxon/MX.38366
Text: Wikipedia (Finnish), CC BY-SA 4.0 https://fi.wikipedia.org/wiki/Lituruoho
