Cottonwood (Populus) -

• Lombardy Poplar (Nigra)
  
• Petrowskiana (Petrowskiana)
  
• Parryi (Parryi)
  
• Japanese Poplar (Maximowiczii)
  
• Balm-of-Gilead (Jackii)
  
• Rouleauiana (Rouleauiana)
  
• Simon Poplar (Simonii)
  
• Quaking Aspen (Tremuloides)
  
• Tristis (Tristis)
  
• European Aspen (Tremula)
  
• Chinese White Poplar (Tomentosa)
  
• Smithii (Smithii)
  
• Inopina (Inopina)
  
• Hinckleyana (Hinckleyana)
  
• Hybrid Balsam Poplar (Brayshawii)
  
• Carolina Poplar (Canadensis)
  
• Balsam Poplar (Balsamifera)
  Balsam Poplar, Black Cottonwood
• Narrowleaf Cottonwood (Angustifolia)
  
• White Poplar (Alba)
  
• Gray Poplar (Canescens)
  
• Eastern Cottonwood (Deltoides)
  Eastern Cottonwood, Plains Cottonwood, Rio Grande Cottonwood
• Swamp Cottonwood (Heterophylla)
  
• Heimburgeri (Heimburgeri)
  
• Bigtooth Aspen (Grandidentata)
  
• Fremont Cottonwood (Fremontii)
  Fremont Cottonwood, Fremont Cottonwood
• Lanceleaf Cottonwood (Acuminata)