hypanthium vs calyx tube

hypanthium and calyx tube both are nouns.

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

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

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

Other synonyms of hypanthium include floral cup.

hypanthium (noun)	calyx tube (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)