Generally, an inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
is considered solitary (of one flower) if a single flower arises from leaf axil(s), or if only one flower terminates an inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
stalk. A plant may, however, bear more than one inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
stalk.
Most of the time it is easy to determine if an inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
is solitary or not, although the inflorescence(s) of some plants fall into either category.