Practice question

Epicalyx represents extra whorl of bracteoles resembling sepals located immediately outside true calyx, forming additional protective envelope in certain Malvaceae and Rosaceae. In Hibiscus rosa-sinensis it comprises 5-7 free linear bracts distinct from gamosepalous K(5), increasing bud protection and providing photosynthetic activity. It is not extra sepals fused within calyx nor fused petals nor reduced calyx vestige. Epicalyx enhances structural defense against herbivory and correlates with valvate calyx, monadelphous androecium and twisted corolla diagnosing Malvaceae floral morphology, serving as taxonomic marker at tribe level within order Malvales.