Glossostigma Diandrum care guide
Glossostigma Diandrum (Glossostigma diandrum) — high light, 20-28 °C, pH 5.5-7, CO2 recommended.
Compiled by Aquairi from published sources · Published · Updated
Overview
Glossostigma Diandrum (Glossostigma diandrum) is an aquatic plant of the family Phrymaceae, listed in the Aquairi knowledge base as an intermediate-level species. It is typically grown under high light with pressurised CO2 injection on nutrient-rich aquasoil. A tiny carpeting plant closely related to the famous Glossostigma elatinoides but slightly easier to cultivate. Forms an extremely flat, dense carpet of small spoon-shaped leaves. Requires good light and nutrition but is more forgiving than its cousin.
Taxonomy
- Family: Phrymaceae
- Genus: Glossostigma
- Scientific name: Glossostigma diandrum
- Common synonyms: Glosso Diandrum
Habitat
Glossostigma is a small genus of Phrymaceae from wetlands of Australia, New Zealand and southern Asia. Plants form low creeping mats in shallow muddy water on full sun. In the Aquairi knowledge base, populations associated with this form are recorded from Southeast Asia, Australia.
Growth requirements
- Lighting: high
- CO2: recommended
- Temperature: 20-28 °C (68-82 °F)
- pH: 5.5-7
- GH: 2-10 °dGH
- Substrate: nutrient-rich aquasoil
- Maximum height: 3 cm
- Growth rate: fast
- Recommended placement: foreground carpet
Placement
Foreground carpet; closely spaced portions root rapidly under bright direct light and CO2, producing a smooth low lawn. In the Aquairi knowledge base this form is recommended for the foreground as a carpet under high light with pressurised CO2 injection, using nutrient-rich aquasoil.
Propagation
Horizontal stems root at every node; trimming the carpet and replanting clipped portions accelerates coverage. Documented propagation techniques for this entry include: horizontal runners.
Common issues
Low light forces vertical growth and stretching; bright light and dense initial planting are critical to a flat carpet.
Propagating Glossostigma diandrum: Dividing the Carpet by Runners
Overview
Glossostigma diandrum is a tiny carpeting plant closely related to Glossostigma elatinoides, which is described as a terrestrial or aquatic, mat-forming herb with small elliptic to egg-shaped leaves only a few millimetres long. Like its relative it forms an extremely flat, dense lawn across the substrate, making it a classic foreground and carpet choice for aquascapes.
It is propagated vegetatively rather than from tops: the plant creeps and spreads by runners, and you increase your stock simply by dividing an existing mat and replanting the pieces.
Propagation Method
Glossostigma spreads fast by creeping runners that root at points along the substrate. To propagate, you divide a healthy mat into many small clumps and plant them out in a loose grid; each clump then sends out its own runners to knit the gaps closed into a continuous carpet.
Step-by-Step
- Lift a section of established carpet and rinse the substrate from its roots.
- Tease the mat apart into small clumps, each with a few leaves and some roots.
- Using tweezers, push each clump gently into the substrate, spacing them out in an even grid with small gaps between them.
- Keep the clumps low and pressed in so they do not float free before they anchor.
- Allow runners to fill the gaps; as conditions stay good the clumps merge into one flat carpet.
Conditions for Healthy Growth
This is a demanding little plant. It is easy and spreads very fast in a CO2-injected tank, and good CO2 lets it grow at lower light because it can divert energy from CO2-capture into vegetative growth. Grown without injected CO2 it needs a great deal of light to stay alive and flat. Pair high light and CO2 with a nutrient-rich substrate, warmth around 20-28 C and soft, slightly acidic to neutral water.
Maintenance
Trim the carpet frequently and deeply enough that the existing lawn can renew itself — cut down until a little substrate shows through, leaving room for fresh growth to root well. Regular trimming, roughly every couple of weeks, keeps the layer thin and stops the lower portion from shading itself and detaching.
Common Challenges
- Growing tall instead of flat — usually too little light; raise light and keep CO2 steady so the plant stays compact.
- Carpet lifting off — an overgrown, ungroomed mat shades its own base and floats away; trim before it gets thick.
- Slow or failing start without CO2 — without injected CO2 you must compensate with very high light, or growth stalls.