Question: What taxon do watermelons belong to?
Paraphrase: What is the name of the taxon watermelons are in?
SPARQL (Wikidata):  select distinct ?obj where { wd:Q38645 wdt:P1582 ?obj . ?obj wdt:P31 wd:Q16521 } 
Answer: Citrullus lanatus, Citrullus lanatus var. lanatus