Genus

• Gardeners typically focus on learning the two-word name, or binomial, to identify plants. The first portion, the genus, is the broader category. In the case of the Japanese maple, the genus is Acer. The Acer genus includes all types of maple trees and shrubs. Knowing the genus is a first step, but it will only assure you a plant is a maple, not that it is a Japanese maple.
  
  

Species

• The second portion of the binomial in a plant name is the species. The species name for Japanese maple is palmatum, which refers to the handlike leaves typical of Japanese maples. Combining the species with the genus completes the botanical name, Acer palmatum. Note that the general category, the genus, comes before the more specific, the species. The genus name is always capitalized; the species name is always spelled out in lowercase.
  
  

Subspecies

• For some plants, botanists recognize subcategories or subspecies. For Japanese maple, botanists recognize three subspecies. These are palmatum, amoenum and matsumurae. Botanists now use chemical analyses to make subspecies distinctions. For gardeners, however, it is the differences in geographic range and leaf, flower and fruit characteristics that make subspecies of interest. Thus, if you may learn a particular Japanese maple is Acer palmatum subspecies palmatum, you know that it will have different qualities than an Acer palmatum subspecies amoenum or Acer palmatum subspecies matsumurae.
  
  

Cultivar or Variety

• The key to finding another Japanese maple just like the one you've admired in an arboretum or a photo you've seen is to find out the cultivar or variety name. Sometimes this is the only part of the botanical name on a plant tag or caption. If you see a plant called Japanese maple Bloodgood, Bloodgood is the name of a specific cultivar, Acer palmatum Bloodgood. Similarly, you may see a tree labeled Japanese maple dissectum, which is Acer palmatum var. dissectum, a variety selected and named for its very finely dissected leaves.