G. transcaucasicus comes, as the name suggests, from Transcaucusus, the region including Armenia, Azerbeijan and Georgia (1), and likely northern Iran (see comment section). The species can generally be found at altitudes of 1600 to 2000m, although it has also been described at heights of 28m below sea level to 2200m (2). It is a plant with supervolute verniation, with leaves growing to 7-20 x 1,5-2 cm. In its wide geographical range, it flowers from December to April, with flowering time often dependent on the altitude at which plants can be found. Flower scapes reach as size of 4-12cm.
In cultivation the plants flower in January to March, though only few specialists grow the plants. It is most likely hardy in western Europe.
G. transcaucasicus in the garden of Cyril Thibo. Posted with permission.