1 | Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611-7800, USA |
2 | Komarov Botanical Institute RAS, Prof. Popov str. 2, St. Petersburg 197376, Russia |
3 | Department of Higher Plants, Faculty of Biology, Moscow State University, 12, 1, Leninskie Gory, Moscow 119234, Russia |
4 | Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden |