ladies' slipper vs lady-slipper

ladies' slipper and lady-slipper both are nouns.

Word	Noun	Adjective	Verb	Adverb
ladies' slipper	Yes	No	No	No
lady-slipper	Yes	No	No	No

As nouns, ladies' slipper and lady-slipper are synonyms defined as:

ladies' slipper and lady-slipper: any of several chiefly American wildflowers having an inflated pouchlike lip; difficult or impossible to cultivate in the garden

Other synonyms of ladies' slipper include lady's-slipper, lady's slipper, lady slipper, slipper orchid.

ladies' slipper (noun)	lady-slipper (noun)
any of several chiefly American wildflowers having an inflated pouchlike lip; difficult or impossible to cultivate in the garden	any of several chiefly American wildflowers having an inflated pouchlike lip; difficult or impossible to cultivate in the garden