calla vs pink calla

calla and pink calla both are nouns.

Word	Noun	Adjective	Verb	Adverb
calla	Yes	No	No	No
pink calla	Yes	No	No	No

As nouns, pink calla is a hyponym of calla; that is, pink calla is a word with a more specific, narrower meaning than calla:

calla: South African plant widely cultivated for its showy pure white spathe and yellow spadix
pink calla: calla having a rose-colored spathe

Other hyponyms of calla include Zantedeschia rehmanii, golden calla.

calla (noun)	pink calla (noun)
South African plant widely cultivated for its showy pure white spathe and yellow spadix	calla having a rose-colored spathe