Practice question

Bract is modified leaf, often reduced, scaly, sometimes brightly coloured, arising at node where pedicel originates, subtending flower and protecting floral primordium during bud development. In Bougainvillea bracts become large petaloid for attraction, in grasses glumes are bracts. It differs from foliage leaf in size and chlorophyll content and from corolla parts by position external to calyx whorl. Floral axis comprises peduncle plus pedicel continuum, corolla whorl of petals. Presence of bracteate versus ebracteate condition helps differentiate families: Liliaceae commonly bracteate, Brassicaceae typically ebracteate raceme without subtending bracts.