Just painted stamen and pistols in the barrel cactus flowers.  On to the addition of the spines. 


 Probably the most well known barrel cactus is the golden barrel, Echinocactus grusonii with its bright yellow spines. Its unusual coloring makes it a popular container plant or a point of interest in the garden. Unlike some of the native barrels with their green color and strong fishhook thorns the golden barrels' thorns are more of a gentle curve.


A Tucson gardener has said this: 

The native Fishhook barrel, Ferocities wislizenii, is common around the Tucson desert and produces large clusters of showy flowers either yellow, red or orange in color. A bright, many seeded pineapple like fruit follows the flower which birds and other desert wildlife eat. The thorns of the fishhook barrel can be treacherous especially around pets.

I once heard a scream in my back yard and had to run outside to see what could be in so much distress. On closer inspection I found a young woodpecker stuck to the cactus with the hooked thorns penetrating the wings. I used pliers to pull the thorns from the cactus and then cut them from the bird. On its release the woodpecker ended up hopping off not flying.