Gladiolus watsonioides is a medium to high (½–1 m), herbaceous geophyte with sword-shaped leaves, flattened in the plain of the stem, and spikes of red funnel-shaped flowers, that is assigned to the iris family.

Gladiolus watsonioides is a medium to high, roughly ½–1 m, herbaceous geophyte with sword-shaped leaves, flattened in the plain of the stem, with spikes of red, curved, funnel-shaped, slightly bilaterally symmetrical flowers.

[1][2] At the base of the stem is a flattened fleshy corm of 1½–2 cm in diameter, which is surrounded by a reddish brown, firm to soft fibrous and membranous tunic, that eventually disintegrates into irregular fragments.

[3] Gladiolus watsonioides was first described by John Gilbert Baker in 1885, based on a specimen collected by Joseph Thomson from Mount Kilimanjaro in Tanzania, and now housed at Kew.

Baker agreed with the assignment of his species to the genus Antholyza, but had to create the new combination A. watsonioides in 1898, to satisfy the International Code of Nomenclature for algae, fungi, and plants.

In 1902, Joseph Dalton Hooker described Gladiolus mackinderi based on a specimen cultivated at Kew Gardens in 1901, which had been collected on Mount Kenya by Halford Mackinder.

Charles Henry Wright described a plant from the Aberdare range as Antholyza speciosa in 1935, which is not the same as Gladiolus speciosus that was described by Carl Peter Thunberg back in 1811.