Most of the melastomes people actually grow — Tibouchina especially — want as much sun as you can give them. Centradenia, a small genus native to Mexico and Central America, is the exception worth knowing about. It flowers reasonably well in part shade, which opens up planting spots that would otherwise rule out this family entirely.
What makes it different
Centradenia is a low, arching shrub, usually under a meter tall, with small pink to magenta flowers and foliage that often takes on a reddish or bronze tint, especially with a bit more light than the plant strictly needs. It's not going to compete with Tibouchina for sheer flower coverage, but for a dappled-shade bed under trees, it's one of the few genuinely reliable flowering options in this family.
It's also more cold-tolerant than most tropical melastomes, handling brief light frost where a Tibouchina would be badly damaged. That combination — shade tolerance plus a bit of cold hardiness — makes it a useful problem-solver rather than a showpiece plant.
Care notes
Give it well-draining, slightly acidic soil, water regularly without letting it sit wet, and prune lightly after flowering to keep the arching habit from getting leggy. It roots easily from cuttings, so one plant from a nursery can be multiplied fairly quickly if you want to fill a larger shaded area.