source
https://www.inaturalist.org/journal/rymcdaniel
"The most convenient way for observers to differentiate the two genera in north central Texas is by observation of the phyllaries."
False Foxgloves (Agalinis) produce attractive, purple blossoms in late summer through fall. The distribution of these species are poorly documented, so our observations can help with that. There are several species in Texas that are quite similar yet unique in subtle ways.
Here's a guide that I put together as an attempt to note distinguishing features: https://docs.google.com/presentation/d/1jQ4yVFHhCZ2Yhy7v_Z3ngp-tZIvOKN3UtCBm0mOBbg4/edit?usp=sharing
Gutierrezia texana
G. texana is much more common in the area than either Amphiachyris species.
https://www.inaturalist.org/journal/lisa281/31314
These three native elms all flower and fruit in the spring, before leaves arrive. The fruit of elms is a flat, rounded samara, with a central seed surrounded by a thin wing. Here's how to identify American Elm, Slippery Elm, and Winged Elm from these samaras.