Assertion: yam's leaf | /r/CapableOf | form hard heads
Facets:
value: very
type: DEGREE
value: under proper temperature conditions
type: OTHER
Source sentences:
text: There are two classes of head lettuce: the butterhead types, such as Bibb lettuce, with soft heads of thick oily-textured leaves, and crisphead types, such as iceberg lettuce, with brittle-textured leaves that form very hard heads under proper temperature conditions.