That explains it. And yet, don't some of them have thousands of "wheat"s?
For example, 3192 pages of "Triticum aestivum"
http://www.ars-grin.gov/npgs/a...
... I see, they call them "subspecies" like
Triticum aestivum subsp. aestivum POACEAE (wheat) RIL-153
Triticum aestivum subsp. aestivum POACEAE (wheat) RIL-152