Muilla lordsburgana P.J.Alexander sp. nov. is described from eastern Lordsburg Mesa in the northwestern fringe of the Chihuahuan Desert, southwestern New Mexico. It is very similar to Muilla coronata, a species known in the Mojave Desert of California and a small area of adjacent Nevada. Compared to Muilla coronata, the style and stigma combined are longer, the anthers are longer, the fruits are larger, and the seeds are larger. It has a short flowering period in March, and is difficult or impossible to find at other times of the year. It is narrowly distributed, limited to a band of deep, coarse, sandy soils derived primarily from granite. Several species that are otherwise uncommon in the area also occur in this habitat, ­­­­­including Logfia depressa, Pectocarya platycarpa, and Plagiobothrys arizonicus. Invasive species, especially Erodium cicutarium in the winter annual flora, are generally dominant. Muillla lordsburgana has probably been overlooked until now because it is not easy to observe and occurs in habitats that are not attractive to botanists.

This dataset includes photographs falling into three categories: 1) photographs of Muilla lordsburgana taken with a Canon 5D Mk. II & Sigma 105mm or Canon 100mm macro lens; 2) photographs of habitat taken with a Canon 5D Mk. II & Canon 17-40mm lens; 3) photographs of Muilla lordsburgana taken with an iPhone SE. Categories 1 & 2 are available as RAW files and as jpg files edited (cropped, resized, exposure & contrast improved, sensor dust removed, location & other metadata added) in Adobe Photoshop. All images in category 3 are unedited .jpgs, with metadata (beyond the default information provided by the iPhone) in an associated csv. The RAW images of flowers were used as a source of measurements used in morphological description of Muilla lordsburgana; they were taken at 1:1, so in the focal plane the long axis is 36mm & the short axis is 24mm.

This dataset also includes a csv providing locations and lists of plants seen for the sites included in the habitat photographs (category 2 above), for sites visited while searching for Muilla lordsburgana, and for sites visited during the flowering period of Muilla lordsburgana (March) within 125 km and 300m elevation of known Muilla lordsburgana sites (i.e., sites when I was not specifically looking for Muilla lordsburgana but should have observed it were it present).