Leuchtenbergia principis in flower

This species, from Mexico, is unusual for a cactus, in that its tubercles, rather than being short and stout, are exaggeratedly long, and crowned with equally exaggeratedly long paper spines:

And as a result looks a bit of a mess:

But every summer, sometimes twice, it produces a beautiful yellow flower, here glistening from the recent rain.

Cheers,

-R