The allelopathic effects of bur buttercup (Ranunculus testiculatus) tissue on selected grasses and forbs varied according to the substratum for germination and growth. The in vitro effects of an aqueous extract of buttercup tissue on germination and root development of five grasses were strongly inhibitory in all cases. However, in soil the effects of buttercup tissue on germination and growth of seven grasses and two dicotyledonous herbs were small to nonsignificant. Deleterious effects were less severe in fine- as opposed to coarse-textured soils. Under field conditions, the ability of seedlings of the grasses to compete with buttercup varied with the species.
Buchanan, Bruce A.; Harper, K. T.; and Frischknecht, Neil C.
"Allelopathic effects of bur buttercup tissue on germination and growth of various grasses and forbs in vitro and in soil,"
Great Basin Naturalist: Vol. 38
, Article 13.
Available at: http://scholarsarchive.byu.edu/gbn/vol38/iss1/13