Per capita at each generation, per stirpes and by representation, for Colorado trustees

The three systems, in one sentence each

Strict per stirpes — the division always begins at the children’s generation, one share per child living or deceased with descendants living; a deceased child’s share splits among that child’s own descendants. In Colorado this is what "per stirpes" means in a governing instrument (C.R.S. §15-11-709(3)).

Per capita with representation — divide at the nearest generation with a surviving member: one share for each survivor there and for each deceased member who left descendants; a deceased member’s share passes down the same way to that member’s descendants. In Colorado this is what "by representation" means in a governing instrument, unless the instrument provides otherwise (C.R.S. §15-11-709(5)).

Per capita at each generation — divide at the nearest generation with survivors; the deceased members’ shares are combined and divided equally among the next generation’s takers, so equally-near relatives take equally. In Colorado this is the division of an intestate estate among descendants (C.R.S. §15-11-106) and the meaning of "per capita at each generation" in an instrument (§15-11-709(2)).

The same family tree can come out differently under different governing words — which is why the instrument controls. In Colorado the words matter twice: "per capita at each generation", "per stirpes" and "by representation" each have a statutory meaning when an instrument uses them (C.R.S. §15-11-709), and intestacy uses per capita at each generation (§15-11-106). A trust may also define its own scheme or name alternate takers, and reading a particular instrument against the statute is licensed-attorney work.