There are 62 Billbergia species in subfamily Bromelioideae of family Bromeliaceae with most native to Brazil.
It was previously (and still seen occasionally) divided into 2 subgenera on the basis that
    Billbergia petals curved back while in Helicodea they coiled up tightly.
According to POWO (Plants of the World Online), GBIF ( Global Biodiversity Information Facility) and
    World Flora Online (Kew) Helicodea is a synonym of Billbergia.

Plants are mainly epiphytic on trees and sometimes on rocks but they will also grow on the ground.
They are medium sized plants with a narrow funnel-shaped basal rosette of leaves.
There may be scales or trichomes on the leaves and inflorescences.

The strap-like leaves, often fewer than other bromeliads may be erect or spreading.
There are spines on the leaf edges as well as one at the tip.
The foliage can be green or mottled, banded or variegated in bright colours.

Terminal cylindrical or spherical inflorescences, on a stalk or scape are often drooping.
There are large mostly red bracts on the scape.
The long, tubular bisexual flowers may or may not be on a stalk or pedicel.

There are 3 free sepals and petals.
Petal colours include blue, green and yellow as well as white.
Colours are bright and petals may have more than one colour.
As the flower ages the petals curl up.
There are small nectary scales at the inside base of the petals.

The 6 stamens, in 2 whorls are free or fused to the petals.
The anthers may lie inside the corolla tube or extend past it.
The inferior ovary of 3 carpels has 3 locules with numerous ovules.
The single style often extends past the petals.
The fruit are berries that are often red or blue.

Billbergia nutans and B. pyramidalis are commonly grown here.
There are hundreds of cultivars.