Complex sentence: Cultigens under the purview of the ICNCP include "cultivars", "cultivar groups", and "grexes"; however, all organisms traditionally considered to be plants (including algae and fungi) are included.
Split into simpler sentences: Cultigens under the purview of the ICNCP include "cultivars", Groups ("cultivar groups "), and"grexes". All organisms traditionally considered to be plants (including algae and fungi) are included.