The species have stems with strong and very wide ribs, with tufts of long simple, two- to three-celled, flagellate hairs in the narrow grooves between them, and large secretory cavities.

The linear to spathulate leaves, are alternate set along the branches, but are shedded early so the plants look leafless most of the time.

The lilac to purple corollas of the disc florets are deeply split, creating five coiled lobes.

The anthers have stump tips, long pilose tails, and produce pollen that is higher than wide.

[5] The following species are recognised:[1] The genus is native to Bolivia, Chile and Argentina.