What's the name of this flower?

Hundred days red is another name for Lagerstroemia indica. Also known as Full House Red and Hundred Days Red. Small deciduous tree with smooth bark, which blooms in summer and autumn and is red, purple or white, and has good ornamental value.

Or: a bunch of red flowers, also known as firecracker red, ivory red, western red (Guangzhou), red under the wall (Beijing), ivory begonia (Yunnan), fireworks (Fujian), perennial herbs to shrubs, Salvia of Labiatae, native to Brazil. Leaves opposite, oval, 7 cm long and 5 cm wide, with serrated edges. Summer and autumn terminal racemes, in a string. The color is mostly bright red, and there are also white flowers (commonly known as "a string of white"). Calyx bell-shaped, the same color as corolla.