Only one species, alpine azalea, belongs to the Loiseleuria genus. The Latin name of this genus is given according to the French botanist J. L. A. Loiseleur-Deslongchamps. This is an Arctic-alpine species found in cold parts of North America, northern Asia and Europe and it got to the southern parts of Europe (Pyrenees, Alps, Carpathians, the north part of the Balkan Peninsula) in the Ice Age. It was able to find proper conditions and to survive until now. This plant is found only in three locations in Slovakia nowadays. Two of these locations are in the Low Tatras National Park and therefore it became a subject of stamp issue connected with this area. These plants prefer rocky acid soils, hillwashes or rocks. It is a low evergreen procumbent shrub that creates carpet cover. The 1-cm-long, opposite leaves are tough, leathery and with revolute edges that enable this plant to survive in extreme conditions. It is frost-resistant and wind-resistant and able to survive in locations with –30° C in winter. New growth buds are created in autumn and when it is warm they start to bloom. The flowers grow at the end of the twig in 2 – 5 pieces. Calyx is red and five-notched, funnel-shaped, bell-like crown is pink, very rarely even white. It is in flower from June to July. Flowers are pollinated by an insect but in inconvenient conditions the plant is able to pollinate itself. The fruit is reddish capsule. Seeds hibernate closed in capsules and next spring they are spread by the wind. It can conduct vegetative reproduction by rooting of end outgrowths. This plant lives to the very high age. In Alps, 75-year-old individuals were found. Alpine azalea is very rare and its appearance is very isolated in Slovakia (the closest locations are distant more than 300 km). This species is protected by law and included in the Red List of Endangered Plants in category of critically endangered species.                                                                                                                                                                                                                     Jaromír Kučera