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Miraculous Spinning Seed of Porcupine Grass
Watch this video to experience the spinning seed of porcupine grass:
The bright-colored grasses crisscrossing the center of the frame are porcupine grass. Its long spear-like seeds miraculously drill themselves into the earth in a counter-clockwise motion that you can actually watch. See video above.
Porcupine grass (Hesperostipa spartea, previously known as Stipa spartea, for anyone who cares) is a particularly fun and interesting plant because of its fascinating seed. The common name refers to its long needles, which apparently resemble the spines of a porcupine, though I think the needle-like fruit best resembles a six- to seven-inch spear. The seed head represents the blade, and the long shaft is known as the awn. As the javelin-shaped fruit falls from the plant, the heavy seed head leads the way and embeds its sharp tip into the soil. As the awn dries, it twirls counter-clockwise until the shaft becomes so tightly wound that the implanted seed head begins to drill into the ground. Humidity and moisture have the opposite effect on the awn, causing it to uncoil, allowing rain or heavy dew to straighten it out. As the awn unwinds, the seed is left in place. The drilling process resumes when the environment dries out, and the cycle repeats until the seed is deposited as far as three to four inches beneath the surface, where the awn decays and the grain germinates. Seeds of porcupine grass can’t help but drill, so much so that they’ve been known to cause fatal wounds in animals. Hence, trust me when I tell you that putting them in your pocket is a big mistake.
The awn of this porcupine grass seed is tightly twisted, as you can see by the winding yellow and black stripes along its length. The pointy seed head of porcupine grass is bearded, with hairs pointing upward to keep it lodged in the soil. As a fun experiment, drop the entire fruit into a tall glass of water and remove it after it has mostly straightened out. Dab it dry with a towel, and then stick the seed head into a small pot of dirt or, if in a pinch, a dry sponge. Now watch. Soon, you’ll begin to see the awn wind like a very slow second hand of a backwards-running clock. See video above.
In June, you can find porcupine grass and their spear-like seeds at prairies and savannas across the Chicago region, including:
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ABOUT MIKE MACDONALD
Mike MacDonald can be described in just one word: passion. And Mike is passionate about Chicago nature.
An internationally published nature photographer, Mike has photographed Chicago’s natural wonders for over two decades: its prairies, savannas, woodlands, and wetlands.