Scarlet pimpernel (Anagallis arvensis)
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Scarlet pimpernel is a low-growing, branching, winter or summer annual, and occasionally, biennial broadleaf plant. It is found throughout California, up to 3300 feet (1000 m), except in the deserts and possibly the Great Basin. Scarlet pimpernel inhabits agricultural land, ornamental landscape beds, turf, water body margins, and other disturbed, open areas. If consumed, it can be toxic to livestock and humans. Toxicity level ranges from virtually nontoxic to fatally toxic and appears to correlate with summer rainfall levels. Although leaves contain saponins and other potentially toxic compounds, it is uncertain as to what substance is responsible for livestock poisonings. If more palatable forage is available, livestock will avoid eating this bitter-leaved plant.
Crop fields, vineyards, orchards, pastures, grassland, turf, gardens, landscaped areas, urban sites, roadsides, margins of vernal pools, streams, marshes, coastal terraces, ocean beaches, and other disturbed sites.
Cotyledons (seed leaves) are narrowly lance, football or egg shaped, hairless, and 1/25 to 1/4 of an inch (1–6 mm) long. True leaves are oval to football shaped with triangular tips, are opposite to one another along the stem, and sometimes have dark glands dotting the lower surface.
The mature plant grows up to 1-1/3 feet (0.4 m) tall. Stems are square in cross-section, and grow upright or prostrate. Leaves are stalkless, oval to football shaped with triangular tips, and sometimes dotted with dark or purplish glands on the lower surface. Leaves are opposite to one another along the stem, or sometimes around the stem in a whorl. Common chickweed, Stellaria media, has similar leaves but rather than the square stems and glandular hairs of scarlet pimpernel, it has round stems and nonglandular hairs.
Flowering takes place from March through July. Flowers have five salmon-orange colored petals, slender stalks, and grow singly between the stem and leaf stalks. On rare occasion flowers can be brick red, bright blue or white. They remain closed during cool or cloudy weather.
Fruits are tiny, round capsules about 1/10 to 1/6 of an inch (3–4 mm) in diameter. They are suspended from downward curved stalks. A lid at the top of each capsule opens and releases several seeds.
Seeds are egg to football shaped, threesided, black or brown, 1/25 to 1/16 of an inch (1–1.5 mm) long, and covered with small wartlike projections.
Reproduces by seed.