Portulaca advena Reichg. & Von Poellnitz (1939), based on adventive specimens collected near Erp, prov. N.-Brabant, Netherlands, and afterwards cultivated in a garden at Nijmegen, appears to be identical with the South American P. papulosa Schldl. (1853). The adventive species of Portulaca found in the Netherlands can be distinguished as follows: 1. Calyx-segments distinctly keeled. Leaves flat, obovate to spathulate, with axillary hairs 0.1—0.8 mm long ............................. P. oleracea L. 1’. Calyx-segments not keeled. Leaves not flat but thick, linear to obovate, with axillary hairs c. 2—15 mm long. 2. Leaves (4—)7—18 mm long. Corolla violet. Seeds bluish grey. ..... P. pilosa L. 2’. Leaves 2—7 mm long. Corolla yellow. Seeds brown to black. .. P. papulosa Schldl.