skopjecollection said:I though the dichtomous splitting thing was under "optional"....
According to my cactus book (Anderson) the species may be solitary or branching. The branching may occur at the base or by division of the growth center. The species is widespread and variable. The central spine, if present, is supposed to be long. Most of the examples I've seen in cultivation have been dichotomously branching, pale yellow flowered versions of subsp. nejapensis, which has no central and 3-5 radial spines.
That said, I cannot offer any opinion on the plant pictured in Stefan's post, beyond the observation that it definitely has a central spine.
This plant came to me with (barely) two heads.
