In lieu of an abstract, here is a brief excerpt of the content:

V E G E TA B L E A R M AT U R E Vegetable armature, they call it, the thorns and spines and prickles that plants bear to our annoyance. While blackberries might explain the fundamentals of such armatures, there are trees in our woods so over-armed that scientists can only speculate as to what drove them to such distraction. Take the honey locust (Gleditsia triacanthos). You’re most likely to run into a tame variety on a street or in a park, where it’s planted because of its fast growth, blow-away leaves,and dappled shade.My college has two nice-sized ones outside its administration building.In the spring,five-inch-long racemes of creamy-white flowers seduce the passersby with their delicious perfume.Come fall,the perfume turns into seed pods filled with an edible,honey-sweet green goo you can dig out with finger or tooth and in which float the seeds.All in all,a lovely tree. But a quarter mile away, along Woods Creek Trail, hiding behind a sycamore, stands a wild honey locust, offspring perhaps of those nearby collegiate trees, since the tree’s native range is the Mississippi and Ohio River valleys.Surrounded by rival trees, this one’s grown tall and straight, unlike its college-pampered, open-spaced relatives. But what draws your attention to this otherwise unremarkable tree are the bouquets of spines scattered along its trunk and branches, each clump with ten to twenty vicious, branching spines, some more than a foot long, each tip ever so much sharper than you’d think, and all intertwined one with the other so, try to grab one, and a dozen poke you. Profligate of pain, the honey locust grows spines everywhere, singles sticking out from branches and bundles from the trunk. Wanting a spine to grace my mantle to remind me of Mother Nature’s nature,I suffered a dozen pokes and prods grabbing one.Findingittwistedeasily ,Ithoughtremovingitbutamoment’sworkbuttookfiveminutes to twist it loose. WhathorribleanimaldidtheancestralhoneylocustdeterwithsuchPentagon overkill? Nobody knows. Whatever it was, it’s no longer around. The pods fall to the ground,where they’re eaten by gray and fox squirrels,white-tailed deer,quail and crows,and possums,as well as cattle and hogs,none of which needs to brave thorns to get to the fruit, although many a human has rued the day he or she VEGETABLE ARMATURE 75 walkedbarefootunderahoneylocust.Oldertreesceaseproducingthornsintheir crowns,so that the upper reaches of the tree are often thornless.Whatever beast drove the tree to defend itself with such extravagance must,then,have been after lower leaves and branches,if not the trunk itself.Think elephant. Which is what Daniel Janzen thought when musing on the evolution of large fruit-bearingtrees,liketheavocado,inthejunglesof CentralAmerica.Mightnot, he wondered, have now-extinct Pleiostocene megafauna such as mastadons and giant sloths guided these trees’ evolution? Others applied Janzen’s idea to bigseeded , large-thorned North America trees like the honey locust. If indeed giant browsers drove the evolution of spines,they did so on more than one continent, because Gleditsia grows in both Americas and in Asia. All twelve species sport thorns,and Swedish botanist Carl Peter Thunberg thought the Japanese version so fearsome he named it horrid. Janzen was not the first to take an interest in America’s megafauna.Two hundred years earlier,Thomas Jefferson had cited mammoth remains to refute assertions of American inferiority made by French naturalist Georges-Louis Leclerc, ComtedeBuffon:“Towhateveranimalweascribetheseremains,itiscertainsuch a one has existed in America, and that it has been the largest of all terrestrial beings. It should have sufficed to have rescued the earth it inhabited, and the atmosphere it breathed, from the imputation of impotence in the conception and nourishment of animal life on a large scale: to have stifled, in its birth, the opinion of a writer [Buffon], the most learned too of all others in the science of animal history, that in the new world, `La nature vivante est beaucoup moins agissante, beaucoup moins forte:’ that nature is less active, less energetic on one side of the globe than she is on the other.” Jefferson’s preoccupation with megafaunal remains led critics to dub him “Mr. Mammoth” and advise, “Go, wretch resign thy presidential chair, / Disclose thy secret measures, foul and fair, / Go search with curious eye, for horned frogs, / Mid the Wild Louisianian bogs: / Or, where the Ohio rolls his turbid stream, / Dig for huge bones, thy glory and scheme.” Artist...

Share