Perianth

Perianth is the term for an undifferentiated calyx and corolla in a single flower, where the individual members - not separable into distinct sepals and petals - are called tepals instead. When the tepals remain distinct they are called apotepalous (polyphyllous), as in Allium sativum (garlic); when they are fused together they are called syntepalous (gamophyllous), as in Allium cepa (onion). In grasses (Poaceae), the per …