just thought i would post photos of the 2 plants i have & their difference. I am not sure if this difference is just due to environment.

Top plant is a shade older I think...hence the caulking around the body and the more pronounced central spine...top one might also have had a bug munching on it at some stage many moons ago too....

i salvaged the first plant from the next door neighbours house after i saw it at an open inspection. it was very neglected

the second plant i picked up on ebay in a comunity pot with notocactus linghausii for $4... the noto had no spines on it at all??? this years growth is now very obvious.

It's a nice little species Darren, grown in full sun itforms nice tight clumps.
Navajoa is right in that centrals are formed on older stems.



Cheers, CP

wow CP yours is a real nice one... how old before it flowers?

regards
Darren

Not sure about age, but I reckon yours should flower anytime now... usually on the mature stems with central spines. usually during winter.

CP