Assertion: cactus's spine | /r/HasProperty | useful
Facets:
value: in identification
type: OTHER
value: often
type: DEGREE
Source sentences:
text: The spines of cacti are often useful in identification, since they vary greatly between species in number, color, size, shape and hardness, as well as in whether all the spines produced by an areole are similar or whether they are of distinct kinds.