Which description best matches a corymb?

• A. A single flower on a stem
• B. Unbranched, indeterminate inflorescence that is flat topped
• C. A panicle with multiple levels
• D. Branched, determinate with a pyramid shape

Answer: (B)

Corymbs are flat-topped arrangements of flowers built on an essentially unbranched axis, where each flower sits on a pedicel of a different length so they all reach about the same height. That alignment creates the characteristic level, plate-like head you see when observing the inflorescence. Because the top is level rather than forming a long, branched cascade, it reads as unbranched with a flat top. This distinguishes it from branched panicles with multiple levels or solitary or pyramidal structures. The key idea to hold onto is that the flat top comes from coordinating flower heights along a short, unbranched axis, which matches the description of an unbranched, indeterminate inflorescence that is flat topped.