If a flower has four petals arranged in a cross, there's a good chance it's in the mustard family. Flowers are organized alphabetically by genus and species. Hover over a photo series to control the images.
Drummond's Rockcress (Boechera stricta)
This plant was formerly known as Arabis Drummondi. The flowers can be mostly white to begin with, in which case they turn lavender as they wither. The example I found had plenty of lavender to begin with. As the flower dies, small spikes—the seed pods—take their place.
Shepherd's Purse (Capsella bursa-pastoris)
Shepherd's Purse is an inconspicuous weed with tiny white flowers. The giveaway is the distinctively shaped seed pods. This introduced species comes from the Mediterranean area, where the seed pods were thought to resemble the leather purses worn by shepherds (in the days before pockets).
Purple (or Blue) Mustard (Chorispora tenella)
Spectacle Pod (Dimorphocarpa wislizeni)
In Albuquerque, Spectacle Pod is a common weed that blooms throughout the warm months. In April 2019, I found it running riot along the lower Embudito Trail. The flowers occur in clusters on tall stalks. The easy way to identify this species is the seeds that form below the flowers. The seeds supposedly look like spectacles; to me they look more like the fronts of the lab goggles I wore in chemistry class.
As summer turns to fall, you may encounter plants where the signature pods are mostly or entirely gone, but where the flowers are still blooming.
Draba, Whitlow-Grass (Draba)
Western Wallflower (Erysimum capitatum)
Western Wallflowers are typically yellow at the elevations where people usually encounter them, including in juniper-pinyon woodlands. At higher elevations they're typically orange-red. On rare occasions they're a stunning red. All of those variants are shown here.
Except for the introduced Broadleaf Pepperweed, which follows, I'll lump the various species in this genus. The tiny individual flowers may be difficult to make out. A close look shows the Mustard Family's classic cross-shaped arrangement of four petals. You can see that in the thumbnail to the left.
Perennial or Broadleaf Pepperweed (Lepidium latifolium)
An introduced species, widely considered a noxious weed.
The mountains around Albuquerque host several species of bladderpod. The newly formed seed pods look like tiny green balloons. (Before rubber, balloons were made from animal bladders, hence the common name.) You may find bladderpod listed under the genus Lesquerella, which now considered a synonym for Physaria.
Jim Hill Mustard, Tall Tumblemustard (Sisymbrium altissimum)
This look like (and is first cousin to) the London Rocket that's such a profuse weed in Albuquerque. One difference is that London Rocket flowers usually are under 4 mm long, while the petals on this species usually are at least 5 mm long.
London Rocket (Sisymbrium irio)