Confusing Formal Constituency With Function Structure

Martin, Matthiessen & Painter (2010: 225):

Groups and phrases are units of the rank below that of the clause. That is, they are the smaller units that realise the functional parts – the constituents – of the clause.

Blogger Comments:

To be clear, here the authors confuse formal constituency — the rank scale — with function structure. It is the groups and phrases that are the constituents of the clause. The "functional parts" are the elements of function structure that the constituents realise.