B. aquatica "Robust Form"
Range: Northern Australia, near the cities of Darwin and Berry Springs
This member of the rainbow plant family is the only one known to grow in semi-aquatic locations that are occasionally flooded, but otherwise are sandy wet soils. It is also found in lagoon shallows. It grows to a length of 45 cm, with a scrambling stem and 4-5 cm filiform leaves. Coloration is typically bright green rapidly aging through shades of rust and maroon, old leaves slowly bending downward to form a skirt. Flowers are borne singly on stalks rising from between leaves along the stem, up to 2 cm across with roughly obovate petals colored bright to deep violet. Seed capsules are unique in this species in often requiring being soaked after maturation in order to release the seeds within. It is isolated from other species in the genus by both habitat and reproductive isolation, capable of but rarely hybridizing with B. liniflora which it often grows near.
Cultivation: must be exposed to smoke water treatment or seeds covered under lightly burning grass to germinate; a 500 ppm GA3 solution soak for 24 hours is also extremely effective. Grow in sandy peat soil under conditions from slightly dampened and flooding occasionally to continual slight submergence, with high humidity and warm temperatures year round. Grow in strong artificial light to full sun, and feed regularly. Osmocote pellets in the soil may be beneficial.
Reproduction and lifespan: Annual. Reproduces through seed only; may be probagable via stem cuttings, but plants may be lankier via this method.
NOTE: Though B. liniflora is generally the only species in the genus considered to be proven out as self-fertile, personal communication with other growers suggest that B. aquatica may also be capable of self-pollination, though greater viability and possibly healthier plants are still gained from cross-pollination of two different clones.
Close-up of B. aquatica "Robust Form" flower. Deeper violet color than is typical on related B. liniflora or rorida.
"Fine form, red plant" version of this species (which gets far redder in highly exposed lighting). Flowers are a slightly paler shade of purple, but still very dark.