1.  barrel cactus(n = noun.plant) - a cactus of the genus Ferocactus: unbranched barrel-shaped cactus having deep ribs with numerous spines and usually large funnel-shaped flowers followed by dry fruits;
is a kind of cactus
is a member of ferocactus, genus ferocactus

2.  barrel cactus(n = noun.plant) echinocactus - any cactus of the genus Echinocactus; strongly ribbed and very spiny; southwestern United States to Brazil;
is a kind of cactus
is a member of genus echinocactus
has particulars: hedgehog cactus, echinocactus grusonii, golden barrel cactus

   any of several large cacti native to the southwestern U. S. and Mexico, having a short cylindrical form with deep vertical ribs and bearing sharp spines. They are classed in the genera Ferocactus and Echinocactus. [PJC]

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