Floral Formula and Diagnostic Features of Hypericaceae

Hypericium perforatum flower. via wikimedia commons

Floral Formula: Ca^4-5 Co^4-5 A^[10-∞] G^[3-5]
                                                                                        

Floral Description: 

Hypericaceae flowers are perfect, complete, usually 4- or 5-merous and usually yellow. The perianth is composed of free, distinct sepals and petals. The androecium in composed of ten to many polydelphous stamens. The gynoecium is superior and syncarpous; it is composed of 3 to 5 fused carpels with parietal placentation (Missouri Botanical Garden). Infloresence is usually cyme, umbel or panical. 

Drawing of Hypericium perforatum. via  delta-intkey.com

Habit:

Trees, shrubs or herbaceous and either annual or perennial