Plant
              
                - Species and cultivars vary
 
                - Annual
 
              
            
          
         
        
          
            
            
              Stem
              
                - Sprawling, vine-like with alternate leaves or bush types with leaves crowded near base
 
              
            
          
         
        
          
            
            
              Leaf
              
                - Broadly triangular to nearly circular to heart-shaped
 
                - Shallow-toothed edges, sometimes lobed
 
              
            
          
         
        
          
            
            
              Flower
              
                - Separate male and female flowers on same plant
 
                - Yellow
 
                - Female has what appears to be small fruit below petals
 
              
            
          
         
        
          
            
            
              Fruit
              
                - Size, shape, color vary by cultivar
 
                - Two general types: winter (left), summer (right) 
 
                - Winter-harvested when rind and seeds mature
 
    
             - Summer-harvested while immature with soft skin and seeds