Question: What is the source of taxon in watermelon
Paraphrase: In watermelon, where do taxons originate from?
SPARQL (Wikidata):  select distinct ?sbj where { ?sbj wdt:P1672 wd:Q38645 . ?sbj wdt:P31 wd:Q16521 } 
Answer: Citrullus lanatus, Citrullus lanatus var. lanatus