Habitat and Ecology
​Biophytum somnians is a charming herbaceous perennial or subshrub native to South America, with a distribution including Southeastern Colombia, Peru, and Northern Brazil. The species name somnians (Latin for 'sleeping' or 'dreaming') refers to its sensitive leaf movement. It is a plant of the wet tropical biome, found in lowland rainforests at lower elevations (around 100-400 metres). It thrives in the highly humid, warm, and shaded understorey, growing in rich, constantly moist soil or leaf litter.
​Description
​This plant is noted for its distinctive, architectural shape, resembling a miniature palm tree or fern. It produces an erect, unbranched stem that is topped by a rosette of pinnately compound leaves. These leaves consist of numerous small leaflets arranged symmetrically, creating a delicate, fern-like whorl. A primary feature of this genus is rapid sensitive movement (nyctinasty): the leaflets fold inward and droop dramatically at night or when physically disturbed or stressed. The flowers are small, borne in a terminal cluster rising from the centre of the rosette. They are typically white or pale yellow, often with a contrasting colour (pink or purple) on the petals.
​Distinctions from other cultivated Biophytum species:
​B. somnians: Tends to be a larger, more robust plant than the popular miniature B. soukupii. It is usually perennial in cultivation, and its leaflets may be slightly more elongated.
​B. sensitivum: Although highly sensitive like B. somnians, B. sensitivum is typically smaller, faster-growing, and often treated as an annual (dying after setting seed), whereas B. somnians is a true perennial shrublet.
​Cultivation
​Biophytum somnians requires a stable, warm, and highly humid environment, making it an excellent subject for a terrarium, vivarium, or warm, bright cabinet in the UK. It needs bright, indirect light or shade; direct, harsh sun will scorch the delicate leaflets. The substrate should be rich in organic matter and retain moisture well, but must also be well-draining; a standard houseplant compost mixed with perlite and a small amount of synthetic peat or coir is suitable. The soil must be kept consistently moist—it is highly intolerant of drought.
​Optimal Daytime Temperature: 21-29 C (70-84 F)
​Minimum Nighttime Temperature: Must be kept above 15 C (59 F).
​High humidity (70%+) is essential. Water with tepid, soft water (rainwater is preferred). Feed sparingly (monthly during the growing season) with a dilute, balanced liquid fertiliser.
​Unique Features
​The main novelty of this plant is its rapid, visible leaflet movement in response to darkness or touch, earning it a place as a fascinating, interactive houseplant. Its erect, miniature, palm-tree appearance provides strong architectural contrast in any terrarium. Its perennial nature and adaptability to consistently warm, humid environments make it a long-term, rewarding foliage plant.
​Specifications
​Plant Size: established plants in pots as can be seen in the photo.
​Plant Family: Oxalidaceae
​Plant Passport: A Biophytum somnians B 140084 C [user input] D GB