The inflorescence of Acanthopsis dispermoides is sessile, a spike embedded among dense, spiny and hairy to fluffy, overlapping bracts. There is an irregular, four-lobed and ribbed calyx at the base of each flower, its tube shorter than its unequal lobes.
The one-lipped corolla is five-lobed, white below and blue or blue-purple in its upper parts. Darker blue to purple veins are longitudinal, roughly parallel and somewhat straight, visible across the bluish part to the upper margins.
The three central corolla lobes are bigger and round-tipped, the middle one biggest, while the outer, lateral pair is small, hairy on the outside and easily overlooked. A flower is about 2 cm long.
Four erect stamens with stout, hard, white filaments arise from the corolla tube mouth. Their dark, bearded anthers cohere.
The flowers may appear from autumn to spring in the rainy season, sometimes only from around midwinter. The inflorescence persists for some time even on dead plants.
Rain causes the compressed fruit capsules to burst open, dispersing the seeds quite far. This explosive action must have earned the plant one of its Afrikaans names of pistoolbos meaning pistol bush (Steyn and Van Wyk, 2015: Taxonomic notes on the Acanthopsis disperma-hoffmannseggiana complex (Acanthaceae, tribe Acantheae), with an interim key to members of the genus. Phytotaxa 219 (1): 01–26; Vlok and Schutte-Vlok, 2015; Leistner, (Ed.), 2000; iNaturalist).