This plant appeared in our Mediterranean garden:




I think the round, prickly things(!) may be seed pods of some sort because at the base there are buds and tiny yellow flowers:




Is it a weed? I've never seen anything like it.

Not sure what cultivar.

I agree, with Springcolor, definitely appears to be Ricinus, we have a few listed in the database: http://garden.org/plants/brows...

They are such beautiful plants but be aware, especially if you have young children or pets ... this plant is highly toxic!

More info and images for comparison here:
http://keys.lucidcentral.org/k...
https://en.wikipedia.org/wiki/...

Thank you so much - fascinating reading in the Wiki article: "According to the 2007 edition of Guinness World Records, this plant is the most poisonous in the world." Beautiful though it is, perhaps I should get rid of it!

Castor. There are several types. Yes, be careful with pets and children; definitly toxic.
I took this photo at a botanical garden in Statesboro, Georgia.

to everyone for the brilliant suggestions - a mystery quickly solved...