Cottonwood
(Populus deltoides)
is dioceous: male and female reproductive organs reside on separate plants.
Males produce pollen; females produce eggs that, if pollinated (fertilized), yield fruits.
Sometimes a "delta"-shaped leaf may host a parasitic leafminer who spends its larva stage within the epidermal layers, feeding on the mesophyll cells.
Juicy buds may be nibbled by Ruffed Grouse, perching precariously on the branches.