ABSTRACT
There is a generally
recognized problem in the purity testing of
certain native species in the Asteraceae
family.
The focus of this paper is to
identify the problem starting with the
history of the “Pure Seed Unit” (PSU)
definitions for Asteraceae in the Rules
for Testing Seeds of the Association of
Official Seed Analysts (AOSA).
The current AOSA Rules are
compared to those of the International Seed
Testing Association (ISTA) as well as the
Canadian Methods and Procedures for Testing
Seed.
Examples and special problems in
testing native Asteraceae species are
presented.
Finally, ideas for new Asteraceae PSU
are introduced.
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