Read the following intricate sentence containing multiple italicized and underlined lexical items operating as distinct parts of speech depending on their syntactic environment:"The direct consequence of their directing the enterprise so direct was a series of unprecedented policy reforms."Identify the correct grammatical classification (part of speech) for each of the three underlined instances of the word root in their respective sequential order.

To correctly identify the parts of speech in this sentence, we must analyze the syntactic function of each word within its specific clause. According to Wikipedia Reference, words can often shift their grammatical category based on their position and role in a sentence (a process known as functional shift or conversion).

1. 'direct' (first instance): Modifies the noun 'consequence', functioning attributively as an adjective.
2. 'directing' (second instance): Formed from the verb 'direct' with an -ing suffix, it acts as a non-finite verbal form governing an object ('the enterprise') while functioning structurally as a participle or verbal modifier within the prepositional phrase.
3. 'direct' (third instance): Modifies the manner of the action implied in the context (meaning directly or straight), functioning adverbially as a flat adverb.

Therefore, the correct sequential classification is Adjective, Participle, and Adverb.