- Latin synonym: Lychnis viscaria, Viscaria vulgaris
- Name also: Red German Catchfly, Clammy Campion (USA)
- Family: Pink family – Caryophyllaceae
- Growing form: Perennial herb.
- Height: 20–40 cm (8–16 in.). Stem erect, unbranched, glabrous, underside of joints sticky and dark reddish brown.
- Flower: Corolla regular (actinomorphic), dark red (occasionally white or pink), 15–25 mm (0.6–1 in.) broad; petals 5, much longer than calyx, entire or notched tips, with corona. Calyx tubular, 5-lobed, dark violet, without epicalyx. Stamens 10. Gynoecium syncarpous, with 5 styles. Inflorescence racemose.
- Leaves: Opposite, rosette leaves winged, stalked, stem leaves stalkless. Blade linearly lanceolate, long-tapered, with entire margins, margin white-haired at base.
- Fruit: 5-valved, 6–9 mm (0.24–0.36 in.) long capsule.
- Habitat: Dry rocky and hillside ridges, sandy and sloping meadows, river banks, roadsides, railway embankments.
- Flowering time: June–July.
Sticky catchfly was originally a plant that preferred rocky outcrops, ridge slopes, dry hills and sandy meadows. It has clearly made use of human activity by spreading to pastures and sunny roadsides. It can handle long periods of drought because its taproot sinks up to a metre into the ground (a typical xerophyte). It is best known however for the reddish-brown sticky substance that covers the upper part of the stem and which has given the plant its common and scientific names. It is thought that the secretion is the plant’s way of foiling predators, especially ants who try to climb the stem and push their way into the flower. The proof of the efficiency of this system can often be seen with one’s own eyes: apart from all kinds of rubbish, many kinds of both winged and wingless insects can be found stuck to the stem. If sticky catchfly is picked for the flower vase the tar gets all over the picker’s hands. Sometimes a pink-flowered version can be found which secretes no liquid at all. Its smaller relative alpine catchfly is (S. alpina) secretes no tar at all, or very little.
At the beginning of summer sticky catchfly’s flowers are busy with queen bees forming new colonies, and this is when the most pollination occurs. When the queen stays in the hive to look after the next generation, the recently-born and small-sized workers are not so good pollinators. Sticky catchfly’s red flowers attract many other insects too: day and night butterflies, flower flies and small beetles. Sometimes pollinators transmit disease as well as pollen from flower to flower, such as parasitic ustilaginales fungi spores. Even the sticky secretion on the stem can’t save catchfly from these demoralizing predators.