Key for Porocystis Radlk.

1	Petals 5, ca. 5 mm long, the blade lanceolate, adaxially densely pubescent; flower disc glabrous Porocystis demerarae
1'	Petals 4, 2.75-4 mm long, the blade deltate-ovate, adaxially glabrous; flower disc pubescent Porocystis toulicioides