calyx tube vs hypanthium

calyx tube and hypanthium both are nouns.

Word	Noun	Adjective	Verb	Adverb
calyx tube	Yes	No	No	No
hypanthium	Yes	No	No	No

As nouns, calyx tube and hypanthium are synonyms defined as:

calyx tube and hypanthium: the cuplike or ringlike or tubular structure of a flower which bears the sepals and stamens and calyx (as in Rosaceae)

Other synonyms of calyx tube include floral cup.

calyx tube (noun)	hypanthium (noun)
the cuplike or ringlike or tubular structure of a flower which bears the sepals and stamens and calyx (as in Rosaceae)	the cuplike or ringlike or tubular structure of a flower which bears the sepals and stamens and calyx (as in Rosaceae)