A Prickly Question

This is our entry in The Daily Post Daily Prompt: Prickle.

This succulent lives in the Glass House of Greenspring Gardens in Alexandria, Virginia. The prickly question:

Is this a cactus?

Really, we’d like to know.

This photo was taken on April 2, 2017. Specs are:

Canon 100D, ISO 100, f/8.0, 1/20 sec, 55 mm