Thanks Mike, for that reply. I

Now, I agree with what you say in part. Clearly I don't believe that
the volume of the infuser makes any difference -- it's the volume of
the water-filled part of the infuser that is important. But... and
here's what I was trying to say... when I fill the infuser in a teaCUP,
the water goes all the way to the top, however, the leaves are
basically at the bottom. Yes, they are unfurling, and they are using up
some of the volume given to them, i.e. they expand and when I'm done
infusing I note that they have expanded to maybe 3 or 4 times their dry
volume depending on leaf type. However, they obviously don't expand all
the way to the top of the infuser.

In the teaPOT, I am unable to fill the infuser all the way to the top.
However, there is about 3/4" of water above where the leaves are. I am
not "limiting" their space to expand in this way, because even with
more water, they would be settled at the bottom. My question only had
to do with whether the amount of water ABOVE the leaves allows them to
infuse faster or better or whatever. The actual expansion of the leaves
is by no means restrained (except perhaps for the most LARGE leaf
greens, like gunpowder pellets or pearls).

Does that make any sense? You still may be right, but I just wanted to
be clear.

To sum it all up, imagine that the leaves will expand to volume X. In
my tea-cup, they do this near the bottom of the teacup, because the
infuser extends all the way to the bottom. In my tea-pot, they do this
sort of suspended in the center of the water space, or maybe slightly
above the center. But their unfurled volume is clearly the same. I
think.