Attributes / relations provided by
♦ 1USDA Plants Database, U. S. Department of Agriculture
♦ 2Ellenberg, H., Weber, H.E., Dull, R., Wirth, V., Werner, W., Paulissen, D. (1991)
Zeigerwerte von Pflanzen in Mitteleuropa. Scripta Geobotanica 18, 1–248
♦ 3Kattge, J. et al. (2011b)
TRY - a global database of plant traits Global Change Biology 17:2905-2935
♦ 4Jorrit H. Poelen, James D. Simons and Chris J. Mungall. (2014).
Global Biotic Interactions: An open infrastructure to share and analyze species-interaction datasets. Ecological Informatics.
♦ 5Robertson, C.
Flowers and insects lists of visitors of four hundred and fifty three flowers. 1929. The Science Press Printing Company Lancaster, PA.