Jasarum steyermarkii G.S.Bunting

• Genus: Jasarum
• Botanical Background: Described by American botanist George S. Bunting (G.S.Bunting) in Acta Bot. Venez. (1977).

• Geographical Range: Endemic to two river basins in SE Venezuela and southern Guyana.
• Environment: Lives submerged in acidic (pH 4–6), nutrient‑poor blackwater under warm (24–28 °C), high‑humidity tropical conditions.

Leaves

• Linear, membranous, dark green
• Up to 30 cm long
• Clear midrib with perpendicular lateral veins

Inflorescence (Spadix & Spathe)

• Solitary emergent spathe (~15 cm), bronze‑green outside and cream inside
• Spadix shorter, unisexual flowers
• Likely insect‑pollinated

Growth Habit

• Perennial aquatic herb with thick rhizome and fibrous roots
• Leaves fully submerged, inflorescences emergent

Light Requirements

• Bright, diffuse underwater light

Watering & Humidity

• Fully submerged; maintain constant water level and high (>70%) humidity above surface

Soil & Potting Mix

• Fine aquatic substrate (peat‑sand mix) in aquarium or submerged planter

Temperature & Fertilizer

• 24–28 °C

• Monthly dilute aquatic plant fertilizer

Division

• Rhizome division is most reliable

Seeds

• Rarely used
• Require warm, acidic water and light for germination

Typical Issues

• Susceptible to algae overgrowth, root rot in stagnant water

Treatment Recommendations

• Regular water changes
• Organic fungicides (e.g., hydrogen peroxide dip) for root rot.

• Only submerged Araceae species endemic to South America
• Likely evolved from seasonal-swamp Caladium ancestors

• Highly prized by specialist aquarium enthusiasts for its rarity and unique form

Wild Population Status

• Predicted as threatened with low confidence
• Habitat degradation is a concern

Market Availability

• Extremely rare
• Available only through specialized aquatic plant nurseries or private collectors