Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Palmate: Broad and flat like the palm of a hand, but usually used in reference to a structure with fingerlike parts branching off of it, like a moose antler.
These other words reference the same concept: palmated, palmately.