genus Wilcoxia
Monica Swartz (Thu, 15 Sep 2016 20:01:18 PDT)

I grow Wilcoxia (Echinocereus) poselgeri collected in S. TX. It needs
big pots for such a thin cactus because of the tuberous roots.
Enormous purple flowers, sometimes five at a time on the top of a
stem smaller than your little finger. It is sensitive to sucking
insects so I always use a systemic insecticide. Sometimes individual
plants die in winter for no apparent reason so it is good to keep
propagating it from cuttings. Others have reported this problem too.
I suspect that older plants may fill their pots with the tuberous
roots and suffocate. One day I'll get around to posting photos on the
Wiki. monica