The Solanaceae

 Plants in the Solanaceae are somewhat variable. Their corollas of 5 fused petals can be rotate, campanulate, funnelform, salverform, or cylindric. Their fruits can be berries or capsules.

For simplicity, the only flower type you will be asked to recognize in this class, is the type exhibited by potatoes, tomatoes, and nightshades. It has a rotate corolla with stamens that point straight forward. The sinuses between corolla lobes may be shallow, or they may be so deep that you need to look closely to see that the petals are actually fused at the base: