Q.Describe the salient vegetative and floral characters of family Compositae (Asteraceae), with reference to its capitulum inflorescence, its floral formula, and its economic importance.

Family Compositae (also called Asteraceae) is one of the largest flowering-plant families, made up mostly of herbs, with alternate leaves showing reticulate or sometimes parallel venation.

Its defining feature is the inflorescence type: a capitulum (head), in which many small, sessile florets are crowded together on a common, flattened or slightly convex receptacle, the whole structure surrounded by a protective whorl of green bracts called the involucre -- this compact arrangement makes the capitulum look, at a glance, like a single large flower, though it is really an inflorescence of many individual florets. Two kinds of florets typically make up the head. The peripheral ray florets are zygomorphic, with their corolla drawn out into a single strap-shaped ligule, and are usually either female or completely sterile, functioning mainly to attract pollinators. The central disc florets are actinomorphic and bisexual, and it is these that show the family's characteristic floral structure in detail: the calyx is modified into a ring of hair-like or scaly structures called the pappus, which later aids in fruit dispersal; the corolla has five petals fused into a narrow tube (gamopetalous); the androecium has five stamens whose anthers are fused together into a tube around the style while the filaments remain free -- a condition called syngenesious, distinct from the various 'adelphous' conditions seen in other families, since here it is the anthers, not the filaments, that unite; and the gynoecium is bicarpellary and syncarpous, but with an inferior ovary (positioned below the other whorls), unilocular, containing just a single ovule attached by basal placentation. …

Start from the capitulum as the family's single defining feature, explain ray vs disc florets, then describe the disc floret's whorls in the same K-C-A-G order used for other families, being careful to name the syngenesious …

• Describing the capitulum as if it were one flower rather than an inflorescence of many florets.
• Confusing syngenesious (anthers fused, Compositae) with monadelphous/diadelphous (filaments fused, other families). …