To my surprise cactus expert Wolfgangb identified an Echinocereus reichenbachii cactus I observed at Lubbock Lake Landmark on May 27 as a subspecies I had not known about, White Lace Cactus of Texas, https://www.inaturalist.org/observations/164055979.
The variety seems to be characterized by a longer and denser thicket of white spines on the crown of the plant. Be on the lookout for these. E. reichenbachii are plentiful at LLL and a variant is easily missed.
This appears to be the first iNat report of this subspecies west of Big Spring. Of course, the identification may be mistaken.
It occurs to me that I found Lace Hedgehog Cacti at LLL in past years that looked different and that I wanted to ID as something else but were still confirmed as the usual subspecies, perbellus. I need to comb through my 135 other observations of E. reichenbachii to see if any are this new subspecies.