Artichoke Artichoke The globe artichoke ("Cynara cardunculus" var. "scolymus") is a variety of a species of thistle cultivated as a food. The edible portion of the plant consists of the flower buds before the flowers come into bloom. The budding artichoke flower-head is a cluster of many budding small flowers (an inflorescence), together with many bracts, on an edible base. Once the buds bloom, the structure changes to a coarse, barely edible form. Another variety of the same species is the cardoon, a perennial plant native to the Mediterranean region. Both wild forms and cultivated varieties (cultivars) exist. This vegetable grows
Variety of finite semigroups finite group is a variety of finite semigroups, while it is not a subvariety of the variety of (arbitrary) semigroups. Thus, Reiterman theorem show that this set can be defined using profinite identities. And Birkhoff's HSP theorem show that this set can not be defined using identities (of finite words). This illustrates why the definition of variety of finite semigroups use the notion of profinite words and not the notion of identities. We now consider the algebraic definitions of varieties. Requiring that varieties are closed under arbitrary direct product implies that a variety is either trivial or contains infinite structures.