The Genus Corispermum L. (Amaranthaceae) in the Baltic States

Abstract The paper presents the data on taxonomical diversity and distribution patterns and dynamics of the Corispermum species in the Baltic States over the last hundred years. Field studies and the herbarium material analyses were carried out. The distribution dynamics was analysed by comparing all known localities of the Corispermum species in two time periods: by 1990, and from 1991 to the present. Analysis of the herbarium material confirmed that currently there are four species in the Baltic States: Corispermum hyssopifolium, C. declinatum, C. intermedium and C. pallasii. The only endemic species to the Eastern Baltic Region, C. intermedium, is considered as typical for annual vegetation on embryonic shifting dunes and other coastal habitats. In Lithuania, this species is considered extinct or almost extinct, as has not been found for more than 30 years, only its hybrids with C. pallasii. The largest and most stable population of C. intermedium has been found on the eastern shore of the Gulf of Rīga in Latvia. Other species such as ephemerophytic C. hyssopifolium and C. declinatum also prefer dry and disturbed habitats. Both have become less frequent in recent years. However, potentially invasive C. pallasii has been observed in the region with increasing distribution dynamics. The Estonian and Latvian herbaria analysis confirmed that all specimens previously identified as C. algidum after re-examination were identified as C. pallasii or C. intermedium and more often as hybrid C. intermedium × C. pallasii.