Craterocapsa congesta grows one or few stalkless, bell-shaped flowers from leaf axils. The calyx tube is short, the corolla ending in five blue petal lobes that curve out, their tips bluntly pointed. The corolla cup base in picture is whitish.
The five stamens have filaments that widen at the base, the filaments hugging the gaps between the petals. The small anthers are white in picture in a ring around the also white but larger stigma at the height of the petal lobes. The ovary is inferior, containing many ovules.
The fruit is a capsule that frees ellipsoid seeds when ripe and the lid at its top opens (Leistner, (Ed.), 2000; iNaturalist).