1836 A. Gray iv. 178 When they [sc. sepals] are united forming one body, the calyx is said to be monosepalous or one-sepaled.
1894 19 318 A very dense-leaved prostrate plant..mostly appearing only one-sepaled.
1933 L. H. Bailey (List II.) 163/1 Monosép-alus: one-sepaled.