Anagallis arvensis

Scientific Name	Anagallis arvensis L.
Common Names	English: Red scarlet, scarlet pimpernel; German: Acker-Gauchheil; French: Mouron des champs
Description	Annual seed-propagated weed with a thin taproot, opens flowers before rain. A. arvensis was used as a medicinal plant against mental diseases.

Characteristic Features

Sessile, opposite leaves.
Orange-red flowers.
Globose fruits.

Cotyledons

Cotyledons spatulate, acuminate, smooth-margined, sprinkled underneath.

Stems

Prostrate, only slightly ascending, not very ramified, square in cross-section, hairless, up to 15 cm (5.9 inch).

Leaves

Round oval to broad ovate, deep green, glossy, with dark dots underneath, entire margin, nearly sessile, crosswise opposed or coroniform in groups of three.

Flowers

Vermilionred, occasionally blue, axillary, long-pedunculate, star-shaped, petals finely dentate, glands ciliate.
Flowers close at night and on cloudy days.

Flowering Period

Early summer - autumn.

Fruit

Capsules papery, 4-6 mm (0.16 - 0.27 inch) in diameter, circumscissile, the style persistent, up to 40 seeds/capsule.

Seeds

Germination usually in late spring. Seeds are dark brown, ca. 0.8 mm (0.031 inch) long, minutely pitted.

Viability Of Seeds

>10 years.

Propagation

By seed.
Some 100 to 400 seeds per plant.

Habitat

Roadsides, pastures, waste grounds, disturbed sites. Neutral, friable soils with high pore volume.

Soil

A. arvensis prefers neutral, friable soils with high pore volume. It occurs typically in moist soil.

Additional Crop Information

Especially summer crops.

Agricultural Importance

Scarlet pimpernell is a weed with high seed densities in the soil seed bank, germination in wide temperature range and low competition (prostrate stem).
The poisonousness of the weed is discussed controversially (be careful at silage-making and feeding!).

Integrated Crop Management

A. arvensis can be easy controlled by mechanical weeding and is easily suppressed by dense crop stands.