How do you classify a platypus? or Hybrid Forms

Mary brought up an interesting point a couple of posts ago, about how to know a poem is a poem. In these days of prose-poems and flash-fiction, microfictions, visual poetry, and flarf (poems generated by Google searches,) how indeed do we define a poem?

It made me think of my training for my first degree, in biology, which is really a science of classification. How do you classify an animal that lays eggs but feeds its young with milk? That has webbed feet and a beak but is clearly no bird?

In my classes, it is sometimes difficult to explain to students, some of whom remain stubbornly attached to the kind of poetry they were exposed to as youngsters: typical 17th century, rhyme and meter, regular stanzas, etc. They just refuse to believe free verse is poetry, or they get frustrated when I show them a poem by a conversational poet, like Frank O’Hara, or, say, a prose poem from Matthea Harvey, or an almost broken-prose piece like Louise Gluck’s “Telemachus’ Detachment:”

“When I was a child, looking
at my parents’ lives, you know
what I thought? I thought
heartbreaking. Now I think
heartbreaking, but also
insane. Also
very funny.”

A genius of tone and unexpected line break, Gluck uses this character’s utterance to show how simple a poem can be.

I use the analogy of a poetry toolbox. There are tools that poets use, that Mary mentioned: rhyme, meter, rhythm, metaphor, imagery, alliteration, line breaks, onomatopaiea…perhaps there are others – jumps in narrative, dream-like tone. But how do you know a poem is a poem? It usually declares itself when you read it out loud.
I was introduced to prose poetry in my very first poetry book, which was my mother’s textbook for her first Freshman English class in college – Introduction to Poetry, by X.J. Kennedy. In the 1969 version, he includes a poem by Karl Shapiro called “The Dirty Word.” Later, in grad school, one of my teachers taught Baudelaire’s prose poetry. How did I know these were poems? Instinctually, I think, the way we learn everything. When I teach prose poetry to my students, I often use examples of haibun by Basho. His haibun combine prose and haiku in an elegant, sometimes disjunctive way. What makes these poems? Well, do they use tools from the poetry toolbox? Do they look like prose, but act/sound/read like poems? Does it lay eggs like a duck or alligator, but is warm-blooded and milk-giving, like a mammal? What are the defining characteristics of “poetry?” What is the poem’s DNA?