Idimanthus amorphophalloides E.G.Gonç.

• Genus: Idimanthus
• Botanical Background: Described by Eduardo G. Gonçalves in Phytotaxa (2018), the genus honors Brazilian plant collector Idimá Gonçalves da Costa for first discovering the species in the wild.

• Geographical Range: Endemic to a restricted marble outcrop in Italva, Rio de Janeiro state, Brazil.
• Environment: Understory herb of semideciduous Atlantic Forest fragments growing on calcareous soils, experiencing a mild dry season yet high humidity.

Leaves

• Ovate‑sagittate blades (5–7 × 4.5–6 cm), medium green and semi‑glossy above, emerging weeks after flowering

Inflorescence (Spadix & Spathe)

• Leafless inflorescences bear a broadly ovate spathe (2–3 × 1.2–1.5 cm) in off‑white to pinkish‑beige and a spadix up to 4 cm long with densely arranged male and female flowers
• No notable scent recorded

Growth Habit

• Terrestrial geophyte with a hypogeous tuber (~1–2 cm diameter) producing inflorescences before foliage

Light Requirements

• Bright, indirect light simulating understory conditions

Watering & Humidity

• Keep soil evenly moist during growth
• Maintain humidity ≥60%
• Reduce watering during dormancy

Soil & Potting Mix

• Well‑draining mix enriched with crushed limestone or marble chips to mimic native substrate
• Use an oversized pot to reduce corm desiccation

Temperature & Fertilizer

• Ideal range 18–28 °C
• Feed monthly with a balanced liquid fertilizer during active growth

Division

• Propagate by dividing tubers during dormancy
• Handle corms gently to avoid desiccation

Seeds

• Fruits produce ovoid seeds with copious endosperm
• Germination likely requires warm, moist conditions but is rarely attempted in cultivation

Typical Issues

• Susceptible to spider mites, mealybugs, and root rot if overwatered
• Ensure good airflow and avoid waterlogging

Treatment Recommendations

• Treat infestations with neem oil or insecticidal soap
• Use fungicide or improve drainage for root rot

• Flowers before leaves—a rare trait among Araceae—and resembles miniature Amorphophallus, inspiring its specific epithet

• Highly prized by aroid collectors for its unusual phenology and rarity.

Wild Population Status

• Classified as Critically Endangered due to extreme range restriction and habitat vulnerability

Market Availability

• Extremely rare in cultivation
• Occasionally found in specialized botanical collections