If you ever work with nomenclatural databases, you will find that a few little Latin words, usually abbreviated, become the bane of your existence: “auctores (auct.)”, “hortus (hort.)”, “non”, “sensu”, “ineditus (ined.)”. All of these are ways of saying, “Yes, I know that this field is labelled ‘scientific name’, but I’m going to put things in here that aren’t valid names and let you try to sort it out.” Something like “Festuca cinerea auct. non Vill.” is a way of saying, “Some botanists are using the name Festuca cinerea in a way that I think is inconsistent with the typification / diagnosis given by Villars”. In other words, someone misidentified some plants. However, when someone puts the name “Festuca cinerea Vill.” on an herbarium sheet, if the plant is not in fact “Festuca cinerea Vill.” then they have simply made an error. They have not created the new name “Festuca cinerea auct. non Vill.” so don’t put that in your nomenclatural database. Or, at least, put it somewhere other than a field that’s supposed to contain names, because this is not a valid name under any of the nomenclatural codes. It can be very useful to keep track of misapplied names in regionally important floras, as a way of indicating where and why past botanists are likely to apply a name to plants in a way that might be otherwise inexplicable. That’s great. Misapplication and misidentification are not nomenclature, so find a good home for it where we won’t think it’s nomenclature. Create a data structure that makes this distinction, and use it.

Much of this stems, I think, from the historic expense of paper and typesetting. As you move further back in the botanical literature, manuscripts get denser and more abbreviated. The reader is expected to infer a lot from changes in font size, indentation, italicization, and spacing. If something looks like a name, is italicized without a latinate ending, and is followed by a number or a date, that’s probably the citation of a type specimen. Of course you know what book would be abbreviated “Ber. Deutsch. Bot. Ges.” because there just aren’t that many botanical works published. Writing “auct. non L.” is a lot more compact than writing out that some authors have applied this name contrary to Linnaeus’s intent, and your reader will know that this is shorthand rather than a new botanical name. But now we have various databases that originated largely by turning this compact and abbreviated style into digital data. Something you can easily infer when reading one entry becomes a colossal mess once you put 100,000 of those entries in the “name” field of a database. The data need to be made explicit rather than left to inference. So, sure, “Festuca cinerea auct. non Vill.” is fine in a 19th century manuscript. Maybe even in a 20th or 21st century manuscript. It does not belong in a database and especially not in a “name” field.

Well, to be honest, I wouldn’t mind if we banished “auct.” entirely. “Hook. non Vill.” at least tells me something potentially useful–that I should expect Hooker’s application of a name to be different than that of Villars. “Auct. non Vill.” tells me nothing. Some unspecified author(s) somewhere misapplied the name. What am I supposed to do with that? I’ll never know when I’m encountering “Festuca cinerea auct. non Vill.” rather than just “Festuca cinerea Vill.” People don’t knowingly and intentionally misapply a name and then helpfully point this out for you. “Auct.” is someone else–unless, perhaps, someone is setting you up for a particularly obscure form of the Liar’s Paradox.

In recent floras and online databases, Ipomoea purpurea is usually considered introduced to the United States as a whole, by way of cultivated plants originally collected in southern Mexico. Most earlier floras agree on this point as well. For instance, Gray (1878, Synoptical Flora of North America) says it is “an escape from cultivation in the Atlantic States”, although it “may be indigenous” in San Diego, California. House (1908, Annals of the New York Academy of Sciences 18: 181-263) says it is “throughout tropical America” but “cultivated and a frequent escape northward”. Wooton & Standley (1915, Flora of New Mexico) give its range as “tropical America , frequently introduced elsewhere”. Kearney & Peebles (1960, Arizona Flora), Correll & Johnston (1979, Manual of the Vascular Plants of Texas), and Martin & Hutchins (1980, Flora of New Mexico) all indicate it is introduced as well.

However, the situation is more complicated. These authors used different taxonomies than our current understanding of Ipomoea. Within the southwestern United States, what we now call “Ipomoea purpurea” was split into two species by Gray (Ipomoea mexicana and Ipomoea purpurea), three species by House (Ipomoea desertorum, Ipomoea hirsutula, and Ipomoea purpurea), three species (the same as House) by Wooton & Standley, two species by Kearney & Peebles (Ipomoea hirsutula and Ipomoea purpurea), two varieties by Correll & Johnston (Ipomoea purpurea var. diversifolia and Ipomoea purpurea var. purpurea), and two species by Martin & Hutchins (Ipomoea hirsutula and Ipomoea purpurea). All of these authors considered Ipomoea purpurea (or Ipomoea purpurea var. purpurea) to be introduced, but the others (under the names Ipomoea desertorum, Ipomoea hirsutula, Ipomoea mexicana, or Ipomoea purpurea var. diversifolia) to be native to the southwestern United States.

Austin (1990, Sida 14(2): 273-286; 1998, Journal of the Arizona-Nevada Academy of Science 2: 61-83) recognized Ipomoea purpurea without varieties and included Ipomoea desertorum, Ipomoea hirsutula, and Ipomoea mexicana within it. Most subsequent works and databases have followed Austin’s taxonomy, but apparently uncritically assigned the introduced status of Ipomoea purpurea to the entire species despite the fact that prior authors had considered many of the synonyms to be native. Austin himself was more circumspect. In 1990 he wrote: “This species is now pantropical because of cultivation, but it was undoubtedly originally Mexican. It occurs in Arizona, New Mexico, and Texas and has been introduced and/or escaped in the Great Plains, the southeastern United States and the north- eastern United States.” In 1998 he wrote that it is “pantropical, widespread in N. Amer.; probably naturalized from Mexico. This is an unusually variable species, at least in part due to human selection. Cultivated forms are always larger than wild forms, but the size of flowers and sepals may vary even in wild plants.” In both cases, he does not explicitly state that this species is or is not native to the southwestern United States.

My own experience, primarily in southern New Mexico, is that our plants neither resemble cultivated Ipomoea purpurea nor occur in the kinds of disturbed habitats that are typically associated with introduced species. During good monsoon years, it is common throughout the mountains of southern New Mexico in shrublands and woodlands, generally below the forested elevations. It can be found along roadsides but has no apparent correlation with them. I consider it to be native in the southwestern United States and can find nothing beyond its close relationship to the cultivated plants to suggest otherwise.