What is the pronouns in in time of silver rain is a poem that describes nature in all its glory?

The pronouns in the sentence are:

• that (a relative pronoun), introduces the relative clause 'that describes nature in all its glory' relating to its antecedent 'poem'.
• all (an indefinite pronoun), object of the preposition 'in'.
• its (a possessive adjective), describes the noun 'glory'.