Xanthosoma riparium E.G.Gonç.

• Genus: Xanthosoma
• Botanical Background: Described by Brazilian botanist Eduardo Gomes Gonçalves, this species adds to the understanding of Xanthosoma diversity in seasonally flooded and riparian ecosystems.

• Geographical Range: Native to southeastern Brazil
• Environment: Thrives in moist to wet soils near freshwater bodies, often in partial shade. High humidity, warm temperatures, and rich organic substrates are key to its natural success.

Leaves

• Large, arrowhead-shaped (sagittate), and a lush green, often with a prominent central vein and smooth margins
• Surface may be matte or slightly glossy

Inflorescence (Spadix & Spathe)

• Inflorescences are typical for the genus, with a pale to yellowish spathe enveloping a cylindrical spadix
• Scent is likely mild and adapted to insect pollination, though specifics are underreported

Growth Habit

• Terrestrial, tuberous species that forms a compact to moderately spreading clump
• Anchors in moist soil and does not climb or form epiphytic structures

Light Requirements

• Bright; indirect light
• Should be protected from direct midday sun in cultivation

Watering & Humidity

• Requires consistent moisture but must not sit in soggy soil
• Benefits from moderate to high humidity, mimicking its native tropical environment

Soil & Potting Mix

• Requires consistently moist soil, especially during the growing season
• Benefits from moderate to high humidity levels

Temperature & Fertilizer

• Ideal temperatures range between 20–30°C (68–86°F)
• Fertilize monthly with a balanced liquid fertilizer during the active growth phase

Division

• Propagated through division of the underground tubers
• Each segment should have at least one growing eye or bud

Seeds

• Propagation is seldom reported and may be limited by availability
• Low germination rates in cultivation

Typical Issues

• Aphids, spider mites, and mealybugs
• Overwatering can lead to tuber or root rot

Treatment Recommendations

• Use neem oil or horticultural soap for pests
• Allow the topsoil to partially dry between waterings to reduce fungal risks

• Improve air circulation to prevent mildew

• Name, “riparium,” reflects its close association with riverbank ecosystems
• Degree of adaptation to seasonal flooding or high moisture soils

• Rare in cultivation, its large foliage and affinity for moist conditions
• Appealing choice for collectors of tropical and riparian plants

Wild Population Status

• Restricted range and the ongoing habitat fragmentation in the Atlantic Forest
• Conservation status may be of concern, though formal assessments are limited

Market Availability

• Extremely rare in cultivation and typically not found in mainstream horticultural trade
• May appear in specialty collections or botanical gardens