If a plant grows near a cave, its roots can grow several meters into the cave. Observations showed that water dropping periodically from the cave ceiling onto plant roots can induce growth against gravity as well as the formation of tiny root hairs. This phenomenon was already described in the Elbe Sandstone Mountains (Germany) in 1975, first discovered in Austria in 2006 (Günther Cave near Hundsheim, Lower Austria) and is now known for a number of caves in Austria. Which plant species are involved in the formation of root stalagmites is not known, yet. For this reason, samples of 18 root stalagmites from 6 caves were collected and determined by molecular genetic methods using four gene sections. Additionally, a classical vegetation survey was carried out around the cave entrance. By combining both methods, six shrub and three tree species from five families could be identified as sources of root stalagmites. With the molecular genetic methods, the genus could be determined in all cases, but the determination at species level was in most cases ambiguous. This shows the still existing limitations in the work with DNA-barcodes in botany and shall serve as a motivating example to fill existing gaps with high-quality barcodes.