Last night while browsing Watson's "The Structure and Life of Bryophytes", I came across some information on the apical cells of mosses. There's a nice page on this here: link
The above link covers apical cells in all bryophytes, but the relationship of the apical cell shape to the final structure of the plant is fascinating, especially in the case of how it works in leafy liverworts.
I hadn't previously noticed this moss phyllotaxis before. Nor had I even heard the word! Lack of botanical background that I'm trying to redress currently.
Wiki page on phyllotaxis
Harvard Morphology of Mosses