The genus Physalis L. is represented in the Netherlands by 5 adventitious species, viz. P. viscosa L., P. peruviana L., P. virginiana Mill., P. ixocarpa Brot: ex Hornem., and P. angulata L. A sixth species, P. alkekengi L., is found in cultivation and occasionally escapes. The species may be distinguished with the aid of the following key: 1. Corolla white, rotate, distinctly 5-lobed. Fruiting calyx orange or red. 1. P. alkekengi 1’. Corolla yellow, mostly with brown or violet-blue spots, widely funnel-shaped; limb nearly entire. Fruiting calyx yellowish or yellowish green. 2. Plant rather densely covered with stellate hairs. Stems prostrate to ascending ... ......................... 2. P. viscosa 2’. Plant without stellate hairs, but with short simple or long jointed hairs. Stems erect. 3. Plant densely covered with long jointed hairs. Anthers c. 4 mm long. 3. P. peruviana 3’. Plant almost glabrous, with few short hairs, which may be mixed with some long jointed ones in the young parts. Anthers c. 1½-3 mm long. 4. Annuals; the young parts with few jointed hairs. Flowering calyx c. 4-6 mm long, divided halfway or less. 5. Corolla c. 8-15 mm long. Anthers c. 3 mm long, curved after dehiscence. Berry purple ................ 5. P. ixocarpa 5’. Corolla c. 6-8 mm long. Anthers c. 1½-2 mm long, not curved after dehiscence. Berry yellowish green ............. 6. P. angulata 4’. Perennial; jointed hairs absent. Flowering calyx c. 8-10 mm long, divided halfway or more ............................ 4. P. virginiana