in July of 2009 I opined that I thought a leaf with a distinct red midrib signaled a flag.
Here is the last leaf prior to a flag leaf on my Ice Cream in 2009:
While observing my dwarf namwahs today I noticed this red midrib:
The pstem is the right diameter for a bloom. The next leaf is emerging, but its too early to tell if it is a flag. I'll know more next week.