All I know is that if I don't water them enough they look like hell. It seems like the Dyckias dry out even faster than the tank types, so I don't really consider them xeric.

The leaves can take a lot of heat and sun and are somewhat succulent, but I was told by someone who should know that they require a good supply of water at their roots or at least do much better that way.

Thanks for the replys. From what you say,it seems 'Mesic' would be the more accurate choice for these thick rooted thirsty plants. After posting this query,I found something about their water needs at the Houston Bromeliad Society web site,as follows:
Dyckia-"altho they will tolerate drought,they thrive on frequent watering while activly growing.However,keep plants on the dry side during cold weather or periods of reduced light.In the summertime,they tend to dry out rapidly;it is helpful to keep them in a shallow container of water"
Hechtia-"Keep the plants well watered when they are activly growing.Cut back on water during the winter when the temps are on the cool side,and the plant's growth slows.Misting does'nt do the Hechtias much good,as the trichomes on their leaves are not adapted to absorb moisture,but keep the leaves cool by reflecting some of the light that falls on them"
So it appears there is agreement on this,from what you both posted and what is written at the Houston web site.

Thank you for your input, Mesic it is ! Bob C.

Here is a link that might be useful: Bromeliad Society Houston

I agree with Mesic. I water mine daily in summer, both outside and in the greenhouse, and I don't feel bad at all hitting them with full strength 20-20-20 from the hose end sprayer. In winter, in the house I only water once a week. In the greenhouse, since the days are shorter (even though I never allow it to get below 55) I reduce watering.
I tend to treat them like my Sanseverias.