How to Use the NLSPN 



To see if a plant name is accepted, first look in the Guide 

 to Family Numbers for the genus of the plant, which is 

 presented in alphabetical order. The guide will refer you to 

 the family name and number. Then look up the number in 

 the list for the appropriate region of the country. Families 

 within each list are listed in numerical order. When you 

 locate the family, find the genus, which is listed in 

 alphabetical order within the family. Under the genus, the 

 species is also listed in alphabetical order. 



If you find the species, you will know that the name is 

 accepted. If the species does not appear in the list, it is not 

 accepted, and you should look it up in the synonymy 

 (volume 2) to determine a preferred scientific name. 



Here is an example of how to use the list. You want to find 

 out if Toxicodendron radicans is the accepted name for 



poison ivy in North America. First, look in the Guide to 

 Family Numbers under T for Toxicodendron. There you find 

 that the genus Toxicodendron is in Family 173, Anacar- 

 diaceae. Next, look in the United States and Canada List for 

 Family 173, Anacardiaceae. There you find Toxicodendron. 

 Then, look for the species radicans within the genus 

 Toxicodendron. You find that Toxicodendron radicans is 

 listed as growing in regions 1, 2, 3 and 6, so you know it is 

 an accepted name. 



If, however, you want to know if Rhus radicans is the 

 accepted name for poison ivy, you will have a different result. 

 First, look in the Guide to Family Numbers under R for 

 Rhus, and you will be referred to Family 173. You will find 

 the genus Rhus, but you will not find Rhus radicans. Then, 

 you will need to refer to the synonymy to determine that 

 the preferred scientific name is Toxicodendron radicans. 



