Riporto qui la chiave del genere come in eFlora of Pakistan
1 Leaves opposite. Flowers solitary terminal. Petals 4 Portulaca quadrifida
+ Leaves alternate or subopposite, Flowers in terminal clusters. Petals 5 or more (2)
2 (1) Leaves usually spathulate or obovate-oblong. Stipular hairs absent
or very minute.
Flowers Surrounded by a 4-leaved involucre. Sepals keeled. Stamens 7-12 Portulaca oleracea
+ Leaves linear to linear-oblong. Stipular hairs copious.
Flowers surrounded by more than a 4-leaved involucre. Sepals not keeled. Stamens 20 or more (3)
3 (2) Root tuberous, somewhat fusiform. Petals lanceolate. Capsule subglobose, apiculate.
Seeds lenticular Portulaca tuberosa
+ Root not tuberous. Petals obovate. Capsule oblong or ovoid. Seeds reniform (4)
4 (3) Leaves subterete, linear-oblong
, Flowers 2-5 cm across. Petals 5 or more, pale brown or yellow spotted at the base. emarginate
. Seeds metallic grey or greyish-black Portulaca grandiflora
+ Leaves linear-lanceolate. Flowers 1 cm across. Petals only 5, not spotted at the base, obtuse.
Seeds dark brown to black Portulaca pilosa