Orthophyletic? was Re: Tree numbers

[Stephen C. Carlson]

Gary Rosenberg <rosenberg at ACNATSCI.ORG> wrote:
>Also, the number of monophyletic groups in a given dichotomous tree of n =
>taxa is 2n-1 and the number of orthophyletic groups is (n-1)(n-2).

I'd never encountered the term "orthophyletic" before.  What does it mean?  Non-polyphyletic (i.e. either monophyletic or paraphyletic)?

Stephen Carlson