Diversity:  A family of 50 genera and over 1,000 species of herbs, shrubs, and trees with two subfamilies, the Clusioideae and Hypericoideae with the latter often treated as a distinct family (Hypericaceae).

Distribution:  Broadly distributed but elements of the Hypericoideae more common North temperate areas and the typical subfamily - Clusioideae - centered in the tropics.

Floral structure:

Significant features:  With very few exceptions plants of the Clusiaceae (s. lat.) show opposite, simple, and entire leaves and the numerous stamens positioned in fascicles or clusters.
 
 

  Hypericum - with fascicled stamens
 

Hypericum - another species with similar androecium - from the  Universitsy of Hawaii

Hypercium - opposite, entire and - in this case - sessile leaves
 

The mangosteen (Garcinia mangostana L.) shows a structure common to taxa of subfamily Clusioideae, an aril ("a pulpy or fleshy appendage, outgrouth or outer covering of a seed - often derived from the funiculus") which is the only part consumed in this "best of tropical fruits".
 

More information on the Clusiaceae (or Hypericaceae)