Ode to a rare Mustard

Thelypodiopsis shinnersii (syn. Mostacillastrum vaseyi) is a rare annual mustard that's seemingly much more rare than previously thought, most likely due to the same old culprits of habitat destruction and invasive grasses.

It was put on my radar by a friend who spotted it growing in Harlingen, Texas and couldn't figure out what it was. I don't know of many native Brassicas in the region either, and the ones I do know certainly were not this. I looked on SEINET and found only a few herbarium specimens, and when I got to the area - A disturbed patch of vegetation with Borrichia frutescens on the edge of an Ebony woodland I searched the area and couldn't find more than 20 plants.

Though I was pretty sure of the ID I still decided to consult Brassicaceae Expert Dr. Ihsan Al-Shabahz for ID confirmation, which came back positive. Nursery owner Mike Heep was familiar with the species, of course, and knew of a roadside patch North of Harlingen around here : 26.194051,-97.611724 but I found the place overgrown with the same invasive grasses and wasn't able to locate any individuals.

Regardless, it's a cool species with glaucous blue sessile leaves with an auriculate base and tiny white flowers, and it likely doesn't go too far inland as it doesn't seem adapted for drought, preferring instead to stick near Arroyos and waterways.