Gymnocoronis spilanthoides

Geographical Origin and Habitat: Botanically known as the Senegal Tea Plant or "False Water Jasmine," *Gymnocoronis spilanthoides* is a voluminous helophyte plant (rooted in water, canopy in the air) native to the tropical river basins of South America (Brazil, Argentina, Peru, Paraguay). In its habitat, it stubbornly clings to the muddy banks of streams, lagoons, and lakes, invading the water's surface. It has transformed into a top-tier invasive alien species in Australia and New Zealand, where it destroys irrigation channels.

Taxonomy & Genetics: It is an interesting dicotyledon of the Asteraceae family (the aster family, the same biological family as the sunflower and the daisy). It possesses the rare gift, among aquatic plants, of developing massive stems with a hexagonal angular section, hollow inside (to allow floating). It is genetically programmed to creep like a green snake on the surface, producing opposite leaves at the axils and spectacular white, spherical floral heads (very similar to jasmine) if grown emersed.

Physical Structure: In the submerged aquarium, the architecture is caulescent, thick, and imposing. The fleshy stems are true hollow trunks of pale green color, which rise mightily supporting opposite, decussate (crosswise), elliptic-lanceolate leaves, with conspicuously toothed and irregular margins, up to 15-20 cm long. It develops thick subterranean roots and formidable white aquatic adventitious roots that float in the water column by the dozens for each internode.

Color & Texture: The entire vegetative apparatus settles on a bright meadow green color, which fades to emerald green in the basal areas. It never takes on reddish or warm hues. The texture of the submerged leaf blade is smooth and very soft to the touch, contrary to the emersed one which is leathery and wrinkled. The wavy and serrated margins give it a wild and unmistakable appearance.

Lighting & CO2: Extremely adaptable. Tolerating a wide range of conditions, it survives easily in poorly lit tanks, although it will inexorably tend to escape the aquarium (elongating to protrude from the water) stripping itself in the lower part. Under medium-strong lighting, it produces closer and more compacted leaves. CO2 is not a necessary requirement for survival, but if inoculated it will transform it into a "monster" with frightening daily growth.

Nutrition & Substrate: An authentic biological vacuum cleaner of colossal proportions. Its impressive aquatic roots will empty the water column of phosphates (PO4), nitrates (NO3), and ammonium (NH4) in record time, infallibly preventing algal proliferations during the start-up of an aquarium. A fertile bottom accelerates rooting, but it can even be cultivated rooted in a piece of floating filter sponge.

Water Chemistry: Being an invasive helophyte weed, water parameters matter very little. It thrives in soft South American waters (pH 6.0), very hard alkaline tap waters (pH 8.5), and immense thermal ranges, from cold aquariums (15°C) to overheated discus tanks (30°C). It tends to heavily alkalize the water in the absence of carbon dioxide due to its massive diurnal carbon absorption.

Space Management & Placement: Its gargantuan dimensions rigidly confine it to the back corners (background) of tanks no smaller than 150-200 liters or, preferably, in huge open tanks or paludariums where it is allowed to surpass the water level to observe its magnificent white bloom. It is the ideal containment plant for aquariums with robust Cichlids, as its thick, hollow stems withstand formidable shocks and pulls.

Pruning: Cutting a finger-thick stem requires serious shears, not small aquascaping scissors. As soon as the plant touches the water surface (and it will do so quickly), intervene by cutting the stem horizontally above a low node (topping). The underlying stump will throw one or two very robust stems within three days. The removed stem, if replanted, will root lightning-fast in 48 hours.

Risks & Diseases: Aside from Potassium (K) deficiency, which manifests as pinpoint holes on old leaves, it is virtually indestructible. The greatest risk is ecological: NEVER release it into local waterways or down the drain. A tiny stem fragment with a single node will regenerate an entire floating forest, obstructing rivers and sparking biological disaster, making you punishable by law in many jurisdictions.