That's a word?

When I was trying to find out the name of the orange flower growing in our ditch, I used the Missouri Wildflowers Guide website. It's useful because it groups flowers by color. There was a snatch of a poem with the picture of my orange flower, the butterflyweed.
Where the butterfly-weed, like a coal of fire,
Blurs orange-red through bush and brier;
Where the pennyroyal and mint smell sweet,
And blackberries tangle the summer heat,

The old road leads; then crosses the creek,
Where the minnow dartles, a silvery streak;
Where the cows wade deep through the blue-eyed grass,
And the flickering dragonflies gleaming pass.
"Dartles." What kind of a word is that? Well, it means to dart repeatedly. So can you apply that to other artle words? Startle? Does that mean to start repeatedly? I don't think so. Start is a reaction (or to react). And startle is to cause a reaction. Are there all that many short verbs that end in -art that you could -artle to make it repeatedly? Perhaps I could build a case for fartle.

That poem segment is from a fairly long piece by Madison Julius Cawein. There are a lot of plants mentioned, which apparently is typical of his work.