Smilacaceae

Smilacaceae, the greenbrier family, is a family of flowering plants. Up to some decades ago the genera now included in family Smilacaceae were often assigned to a more broadly defined family Liliaceae, but for the past twenty to thirty years most botanists have accepted Smilacaceae as a distinct family. It is considered that the two families diverged around 55 millions years ago during the Early Paleogene possibly near the boundary between Paleocene and Eocene. One characteristic that distinguishes Smilacaceae from most of the other members of the Liliaceae-like Liliales is that it has true vessels in its conducting tissue. Another is that the veins of the leaves, between major veins, are reticulate (net-shaped), rather than parallel as in most monocots. The APG II system, of 2003 (unchanged from the APG system, of 1998), recognizes this family and places it in the order Liliales, in the clade monocots. Earlier it was a family of two genera, Heterosmilax and Smilax, but DNA studies have shown that Heterosmilax has arisen from Smilax and the two genera are now merged. This results in Smilax being the only genus in Smilacaceae with ca 255 known species.The family occurs throughout the tropical and warm temperate regions of the world. Members of this family typically have woody roots and a climbing or vining form. Some have woody vining stems, often with thorns, while others are herbaceous above ground and thornless.