Echinopsis leucantha is a handsomely spined cacti from Argentina. Globular at first it grows more columnar with age and sometimes offsets. Large white trumpet shaped flowers appear in spring and summer.
      I like the way the spines vary on this one, they range from purple with a gold tip then turn gold with a black tip as they age. It's very colorful.
     Update mid June 2007. One of the two in the garden flowered for me. Unforunately it was a cloudy day and the pictures didn't come out as good as I would have liked.

Flowering in June

A closeup