Per stirpes is a Latin term meaning "by roots," or by representation. The term is often used in wills and trusts to describe how to carry out a distribution when a beneficiary dies before the person whose estate is being divided. Under per stirpes distribution, children take among them the share which their parent would have taken had he survived the decedent. The children stand in a representative capacity to their parents.
Another way to express the same intention is to provide "…to her children, by right of representation, share and share alike," which is clear to the non-lawyer. If there is no provision for distribution to children of a predeceased child, then the gift will become part of the residue (what is left after specific gifts), and then the grandchildren may not share if there are surviving children of the giver.
Per stirpes distribution may take place under a will or if a person dies without a will (intestate). State laws of descent and distribution govern intestate distribution and describe any per stirpes distribution that may take place a person in the line of descent is deceased and their children are able to step into their place in the line of inheritance.
Literally, the term per stirpes means by roots or by stock. When used in a will it relates to the distribution of the testator’s property. "Per stirpes" is defined as proportionally divided between beneficiaries according to their deceased ancestor's share. It is a will provision which specifies that the testator’s property is to be divided proportionally between beneficiaries according to their deceased ancestors share. For example, if a will states that the estate is to be divided between A and B, per stirpes, then if A predeceases the testator, the estate will be split between B and A’s children. When descendants take representation of their parent, they are said to take per stirpes; that is, children take among them the share which their parent would have taken, if living.
State laws vary, so local laws should be consulted for applicable requirements.