Lactuca tatarica (L.) C. A. Mey., in the Netherlands up till now known only as an adventitious species found in the harbour of Rotterdam, appears to have established itself in Rottumerplaat, a small island between Schiermonnikoog and Rottum (Westfrisian Islands). In 1967 about 200 plants were found; in 1968 this number has increased to at least 700.