Wachendorfia thyrsiflora, the marsh butterfly lily,[1] is a plant species of 0.6–2.5 m (2.0–8.2 ft) high when flowering, that has been assigned to the bloodroot family.

[1] The marsh butterfly lily is a perennial herbaceous plant of 0.6–2.5 m (2.0–8.2 ft) high, that grows from an irregular, more or less cylindrical rootstock of up to 15 cm (5.9 in) long, sheathed by the overlapping bases of the leaves and that produce roots from the nodes.

[3][4] W. thyrsiflora differs from W. paniculata, which is a small to large, 0.1–0.9 m (0.33–2.95 ft), deciduous herb with apricot, yellow or orange flowers in a lax to dense panicle, with leaves narrower than 2 cm (0.79 in), and that may grow in dry and wetter circumstances (not a large to very large, 0.6–2.5 m (2.0–8.2 ft) high, evergreen herb with golden yellow flowers in a dense spiky inflorescence, with leaves mostly much wider than 1.5 cm (0.59 in), and that is restricted to damp environments).

W. brachyandra has apricot to pale yellow flowers in a lax panicle, clustered stamens, which are like the style less than half the length of the tepals (not golden yellow flowers in a dense cylindrical inflorescence, diverging stamens and style of at least two thirds as long as the tepals).

[3][4] The first description of the marsh butterfly lily was published in 1700 by the English botanist Leonard Plukenet in his book Almagesti botanici mantissa.

In 1739, Johann Philipp Breyne described and illustrated Asphodelus latifolius in his book Prodromus fasciculi rariorum plantarum, but these names predate the start of Linnaean taxonomy in 1753 and are therefore invalid.

Richard Anthony Salisbury created the name W. elata in his book Flora Capensis - sistens plantas promontorii Bonæ Spei Africes - secundum systema sexuale emendatum of 1811.

In their 1992 revision of the genus Wachendorfia, Nick Helme and Hans Peter Linder conclude that W. elata is a synonym of W.

[3] The genus Wachendorfia is named in honor of Evert Jacob van Wachendorff, professor of botany and chemistry and later rector at the University of Utrecht in the 18th century.

[3] The anthers and stigma however are so far from the source of the nectar at the merged bases of the three upper tepals, that smaller insects, including honey bees cannot be effective pollinators.

[1] W. thyrsiflora grows from sea-level to approximately 1,200 m (3,900 ft) altitude, in permanently moist environments such as the banks of streams and seeps.

It flowers in spring but blooms can often be found during summer, probably reflecting that this species does not suffer from water-stress because it grows in permanently moist environments.

[6] The marsh butterfly lily is easy to grow and particularly suited for moist conditions in the full sun or light shade.