Chiltepín vs Pequín

These are the same plant by species and variety, Capsicum annuum var. glabriusculum, and the names get used for each other across the whole range. The Lady Bird Johnson Wildflower Center lists chile pequin, chile tepin and bird pepper as common names for one taxon. The working distinction is shape. A Chiltepín is round, a pea-sized ball. A Pequín is oblong, a small bullet. Where a population is round-fruited people say tepín, where it is oval they say pequín, and the plants themselves do not care.

What they share matters more than what separates them. Kraft and colleagues, in PNAS in 2014, call wild C. annuum var. glabriusculum the ancestor of every domesticated C. annuum, from the bell pepper to the Jalapeño: a perennial shrub with dozens of erect, globular fruits that birds eat and pass. Their four lines of evidence put the domestication of C. annuum in central-east or northeastern Mexico. The erect fruit is not decoration. Tewksbury and Nabhan showed in Nature in 2001, in work that Bosland's group and Kraft's group both build on, that capsaicin deters mammals, which chew seeds, without deterring birds, which pass them intact. A wild chile that holds its fruit up above the leaves is advertising to the one customer it wants.

The Chiltepín is the only chile native to the United States, and it has a preserve. The U.S. Forest Service set aside the Wild Chile Botanical Area in 1999, 2,500 acres around Rock Corral Canyon in the Tumacácori Mountains of the Coronado National Forest. It holds the largest wild chile population in Arizona, one of about ten known in the state, at the northern edge of the plant's range. Texas took the political route. The legislature named the Chiltepín the state native pepper in 1997 by House Concurrent Resolution 82, two years after it named the Jalapeño the state pepper.

In the kitchen both are dried and crushed rather than eaten fresh. The heat of the Chiltepín is sharp and fast and leaves quickly, which is why a Sonoran cook can crush one over a bowl of beans without ruining the meal. The Pequín is the one that ends up in bottled sauces and in dried bags across Texas and northern Mexico, where it grows semi-wild in fencerows and under larger shrubs that shade it from frost. Both are picked by hand from plants nobody planted, which is why they cost what they cost.

Sources

• Lady Bird Johnson Wildflower Center, Native Plant Database: Capsicum annuum var. glabriusculum (Chile pequin)
• Kraft et al. 2014, PNAS 111(17): Multiple lines of evidence for the origin of domesticated chili pepper, Capsicum annuum, in Mexico (doi:10.1073/pnas.1308933111)
• Bosland and Baral 2007, HortScience 42(2): 'Bhut Jolokia', the World's Hottest Known Chile Pepper is a Putative Naturally Occurring Interspecific Hybrid (doi:10.21273/HORTSCI.42.2.222)
• U.S. Forest Service, Celebrating Wildflowers: Chiltepine or Bird Pepper (Capsicum annuum var. glabriusculum)
• Texas State Library and Archives Commission: Texas State Symbols