The white flowers of Merciera leptoloba grow in crowded spikes near stem tips. The flower has a long thin corolla tube of up to 1,5 cm in length. Five narrow corolla lobes spread widely.

The style does not protrude from the corolla mouth in this species, but does in M. brevifolia that also has white flowers. The stamens are, however, exserted far. The flowers that appear in summer have a curry-flavoured scent.

The fruit is a one-chambered capsule that produces one seed. The specific name of leptoloba meaning thin lobe, refers to the fruit capsule (Bean and Johns, 2005; Burman and Bean, 1985; www.theplantlist.org).