A thorn by any other name

When dangerous situations arise for plants, the choice between flight or fight is a simple one. They abide by the stand your ground law and always fight. Such a lifestyle choice means that plants employ a variety of weapons to stave off extinction. Thorns are one of the more obvious botanical defenses. Their appearance is a clear warning not to trample and no herbivore would like a mouthful of sharp spines.

No one will disagree that thorns hurt, but would a thorn by any other name hurt as much? In everyday language usage, we may refer to any sharp plant appendages as thorns, but botanically these sharp protrusions can be thorns, spines or prickles. Their true names are tied to the tissue from which they developed. Thorns are derived from shoot material and are actually branches modified to terminate in a sharp point. Spines are leaves modified to be entirely spike-shaped or barbed along the edges (like holly). Everything else is considered a prickle. So, roses actually have prickles along their stems, not real thorns. Regardless of what term is used, the effect on herbivores and other careless animals that would otherwise trample them is the same.

(A) Thorns and spines are derived from shoots and leaves respectively, and have vascular bundles inside. (B) Prickles (like rose prickles) don’t have vascular bundles inside, so they can be removed more easily. Credit: CASF via Wikipedia

Botanically speaking, Poison’s Bret Michaels was incorrect when he sang “Every rose has its thorn.” I’m willing to give him a pass on accuracy because I’m scared to know how he would’ve rhymed prickle in the subsequent line. Beyond this, modern horticulture is proving him wrong on the entire premise of his song- that all beautiful and good things must have a dark and dangerous side. This may work for the image of a rock star, but plant breeders are diligently trying to disentangle the pretty from the prickly. Some thornless roses are commercially available, but the trait isn’t always stable and thorns can appear when these plants experience certain environmental conditions. For now, the genetics of rose prickles remains a mystery, but eliminating this trait will continue to be the focus of rose breeders and plant scientists.



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One thought on “A thorn by any other name

  1. Pingback: Blackberries: Jewels of Spring | New Under The Sun Blog

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