Over much of its range Lapeirousia pyramidalis has a fairly consistent appearance. Plants are compact with broadly obtuse floral bracts, and the flowers are white to pale blue or pale pink to lilac with a perianth tube 25–35 mm long, slightly curved and wider in the upper 5–7 mm, and always strongly scented, both during the day and in the evening. In the west of its range, in the Olifants and Biedouw River valleys, and at Karoo Poort to the south, plants segregated as subsp. regalis are distinguished by bright red, purple, or dark violet flowers with a long, nearly straight perianth tube, 35–55 mm long, and have no discernable odour. As far as known, the two never grow sympatrically but their ranges are more or less complementary. They also favour different habitats: subsp. pyramidalis normally grows on shale and clay soils, but subsp. regalis has only been recorded on stony sandstone ground. There is also a marked size difference between the seeds of the two subspecies. Over much of its range subsp. pyramidalis has seeds 1.7–2.0 mm diam., but subsp. regalis has seeds ± 1/2 this size, 1.0–1.2 mm diam. The floral differences between the two subspecies reflect a shift in pollination strategy. Strongly scented subsp. pyramidalis is thought to be pollinated primarily by sphinx moths, which are most active at sunset and at night, whereas subsp. regalis is pollinated by long-proboscid flies.

Lapeirousia pyramidalis has a somewhat confused taxonomic history. The species was described by the French biologist, J.P.B. Lamarck in 1789, based on a collection attributed to the botanist, Philibert Commerson (1725–1773), but probably collected by his colleague, Pierre Sonnerat. Plants cultivated in Vienna were described as Gladiolus fissifolius by N.J. Jacquin in 1791, and the fine illustration published shortly thereafter shows this clearly to be the same as Lamarck’s species. For over 150 years the species was known by the later epithet, L. fissifolia and only after 1971 as L. pyramidalis.