Maclura Pomifera: Neither Apple Nor Orange Jon Hetman
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Maclura pomifera: Neither Apple Nor Orange Jon Hetman hough I confess that plants held little ing else seems to find these forbidding fruits sway among my childhood interests, a the least bit appetizing. Nothing, that is, that Tfew specific trees stand out in my early still exists. In her book The Ghosts of Evolu- recollections, all due to their memorable fruits. tion, author Connie Barlow suggests that mam- A seemingly ancient apple tree in a neighbor’s moths, mastodons, and other large herbivores of front yard was a climbing favorite, and bore the North American plains ate Maclura fruits small, mottled green fruits that were a delight and were its dispersal agents before humans to eat as long as you didn’t overindulge. Behind evolved their own interests in the plant. my grandparent’s garage in central Florida, a Although the exact details of the original moss-covered orange tree provided fragrant collection of this monotypic species remain spring flowers and slightly sour fruits that murky, we know that Maclura was among the remain indelible sensations of my youth. But botanical specimens gathered by Lewis and the fruits that perhaps fascinated me most Clark on their transcontinental expedition of belonged to an Osage orange tree that grew near the American West. By studying saplings subse- my elementary school—large, hard as baseballs, quently cultivated in the Philadelphia garden of and looking to us like green brains, the bumpy Bernard McMahon, Constantine Samuel Rafin- orbs with their citrusy aroma were a delightful esque produced the first botanical description of mystery that inspired a number of ingenious the tree in 1817, naming it Ioxylon pomiferum, games of our own design. or “poison apple.” Perhaps unaware of Rafin- In earlier days, Osage orange (Maclura esque’s classification, Thomas Nuttall offered pomifera) garnered significant interest among his own description the following year, hon- people of its native Oklahoma, Arkansas, Mis- oring American geologist William Maclure souri, and Texas, though for very different rea- with its generic epithet and proposing auran- sons. Hunters in the Osage tribe fashioned war tiaca (“orange colored”) as its specific epithet. clubs and bows from the tree’s bright yellow Nearly a century later, Germany’s Camillo Karl heartwood, which proved stronger than oak and Schneider argued for the name that has stuck to as tough as hickory. Early settlers in the Ameri- this day, pairing Nutall’s generic Maclura with can frontier called it the hedge apple, planting a derivation of Rafinesque’s specific, pomifera. it in thicket-like rows so that the thorny, inter- Coincidently, this Teutonic connection to lacing branches sheltered fields from wind and Maclura is compounded in the Arboretum’s provided an impenetrable animal barrier. As most spectacular accession (471-36-B) of the historian Paul Landacre famously described it, plant, a female obtained in 1936 from the Her- an Osage orange hedge was “horse-high, bull- mann A. Hesse Nursery of Weener, Germany. strong, and pig-tight.” Growing today on a steep bank near the Centre For me though, even as an adult, it’s the fruits Street wall across from Faulkner Hospital, the of these dioecious trees that really excite the tree exhibits the criss-crossing, nearly horizon- imagination. If you cut one in half—and you tal branching that once made the species so may need a saw to do so—you’ll discover a desirable as a hedging plant. It is 36 feet (11 tough, pithy core surrounded by a couple hun- meters) tall and its two trunks have diameters dred small seeds. Like other members of the at breast height of 14 and 16 inches (36 and Moraceae (mulberry family), Maclura bears 40.5 centimeters). Visit it in autumn, when its a true multiple fruit composed of numerous limbs bend beneath the weight of its fruits and separate ovaries, each developing from a sepa- its glossy leaves turn yellow, and you’ll likely rate female flower. In fact, the fruit’s distinc- acquire fond associations of your own with this tive bumps—and their accompanying black, most singular of American fruiting trees. hairlike styles—rise from the fruit’s numerous, tightly-packed ovaries. Though squirrels rip Jon Hetman is the Arnold Arboretum’s Communications into fallen fruits to consume the seeds, noth- and Stewardship Officer. .