The poem <em>"Song of Myself", by Walt Whitman</em>, is considered a <em>free verse poem</em> because of the following characteristic: It isn't built from specific rhyme metrics. Its verses s<em>eem like prose speech</em>, they are almost like <em>statements.</em> <em>The poem doesn't have any kind of metric</em>, as it can be observed in this passage:
"Creeds and schools in <em>abeyance</em>,
Retiring back a while sufficed at what they are, but never <em>forgotten</em>,
I harbor for good or bad, I permit to speak at every <em>hazard</em>,
Nature without check with original <em>energy</em>".
During the entire poem, <em>no rhymes match</em>. That is a <em>typical characteristic of free verse poems</em>. Therefore, the characteristic that makes "Song of Myself" a free verse poem is its<em> lack of rhymes that follow a metric</em>.