Gentiana cruciata

Description

Gentiana cruciata is a hemicryptophyte scapose plant of small size, reaching on average 20–40 centimetres (7.9–15.7 in) in height. It has erect stems, the leaves are large, ovate-lanceolate, semiamplexicaul, about 3–8 centimetres (1.2–3.1 in) long. The flowers are violet-blue trumpets with 4 petals, clustered in the axils of upper leaves. The flowering period extends from June to August. The flowers are hermaphrodite and pollinated by insects (entomogamy). The fruit is a capsule. The seeds are dispersed by gravity alone (barochory).

Distribution

Gentiana cruciata is widespread in most of Europe (except Portugal, Great Britain and Scandinavia) and in Western Asia.

Habitat

This plant prefers dry calcareous soil in forest edges, bushy slopes, pastures, grasslands and dry meadows, at an altitude of 200–1,600 metres (660–5,250 ft) above sea level.

Host for Parasitic Phengaris rebeli

The Phengaris rebeli is a butterfly of the Phengaris genus that parasitizes the G. cruciata plant as a source of nutrition. Female P. rebeli lay their eggs on the undersides of the leaves of the G. cruciata plant and three to four weeks later, the P. rebeli larvae emerge and begin to feed on the seeds and flowers of this grassland plant. After the P. rebeli reaches its fourth larval instar, it molts and drops to the ground to be picked up and brought to the Myrmica schencki ants' nests.

The female P. rebeli prefers to lay her eggs on G. cruciata growing in clumps rather than individual plants, and on the taller plants, as they are less shaded and allow the eggs to grow and develop faster. Also, she was most likely to oviposit on the adaxial (upper surface) of the leaf and least likely to oviposit on the stalks of the stem.