> About 5mm diameter is the biggest I've heard of, on U. humboldtii
> and vulgaris (though my vulgaris has never made any more than 2mm.)
I haven't seen the tropical giants mentioned but I can vouch from experience
about the trap size that can occur in U. macrorhiza (vulgaris). In northern
Canada (near Mayo, Yukon Territory) I found very large specimens growing in
the shallow end of a marshy lake. The plants were up to 3/4 of a metre long
and some of the older traps were approximately 4 to 5 mm in diametre.
When you would pick plants out of the water and hold them up to examine
them, the traps sounded like a bowl of rice crispies cereal after you add
milk; there would be many audible snap, crackle and pops as they triggered
and snapped shut with air. These giant traps ranged in colour from a usual
green for the newer traps, to a light purple or blackish purple for the
older traps.
Due to the large size of the plants, they photograhed nicely and Gord
Snelling used a shot of these same plants in an article he wrote on aquatic
plants for aquariums and had published in Aquarium magazine a few years ago.
If I come across the issue and year I'll post it here for any one who may be
interested.
- Randy