Nano Nursery · Rare Carnivorous Plant Encyclopedia
The story of Genlisea barthlottii connects a specimen collected near Kindia in 1906 with a plant formally named ninety years later. Its flowers rise above a small carnivorous plant adapted to a short growing season. For growers, its most consequential feature is its annual life cycle: keeping a plant wet does not necessarily keep it alive after seed production.
A name anchored to an old collection
Kew accepts Genlisea barthlottii Porembski, Eb.Fisch. & Gemmel and records its native range as Guinea to southwestern Ivory Coast. The species was published in 1996 in Adansonia, volume 18, with the name on page 152. Kew treats it as an annual of the wet tropical biome. A description restricted to Guinea therefore understates the range in that current taxonomic treatment. [1]
The Paris herbarium holds holotype P00057042, collected by C.H.O. Pobéguin under number 1358 in August 1906, around Kindia. Its label describes sandy, partly marshy ground and dark blue flowers. It also describes the plant as fairly common there. That is a valuable observation from the collection event, not evidence that the species is common across its range today. [2]
The type is the specimen to which the name is permanently attached. It is particularly useful when comparing historical descriptions, because a flower colour reported in the field can be lost when the plant is dried. A modern living accession still needs its own identification; a match in country of origin is only a starting point.
The features that distinguish it
The key in Porembski, Fischer and Gemmel’s original paper separates G. barthlottii from two other West African species using the hair covering and spur. Both barthlottii and G. stapfii have glandular hairs mixed with smaller non-glandular hairs on the inflorescence. In barthlottii, relatively long-stalked glands, about 0.4 mm long, are confined to the upper part of the ovary, and the spur is generally longer than the lower corolla lip. In stapfii, shorter-stalked glands, about 0.2 mm long, cover nearly the whole ovary, and the spur is generally shorter than the lower lip. [3]
The same key distinguishes G. hispidula by its non-glandular inflorescence and densely bristly, non-glandular ovary and calyx. [3] These are close-up characters. Photograph the flower from the side to show the spur, then examine the ovary with magnification. A front view alone cannot document all the distinctions. The word “generally” in the spur comparison also matters: use the combination of characters rather than one measurement as an infallible test.
Seasonal habitat and the annual life cycle
Fleischmann’s synthesis places G. barthlottii among the African annuals associated with short-lived wet habitats on rock outcrops and ferricretes. These wet flush communities can disappear as the dry season advances. His observations report that barthlottii, G. stapfii and G. subviridis died after seed production even when cultivated in permanently wet conditions. He interprets them as monocarpic annuals: plants that reproduce once and then die. [4]
For a grower, this makes seed production central to maintaining a line. Continued watering cannot be assumed to turn an annual into a perennial. At the same time, a sick seedling should not be written off as normal seasonal decline; the timing relative to flowering and fruiting is essential. These observations support planning for replacement generations, but they do not provide a tested storage interval, sowing temperature or germination timetable for this species.
The same phylogenetic treatment places barthlottii in section Africanae, whose fruits are held upright rather than strongly recurved. [4] Recording the fruiting stem therefore adds useful evidence after the flowers have faded.
The concealed carnivorous structures
Genlisea has green leaves above ground and modified, non-photosynthetic trapping leaves below it. It lacks a conventional root system. Brittnacher’s 2022 article demonstrates a way to observe these structures by suspending a planted mesh basket in a water reservoir, allowing traps to extend through the openings. The outer reservoir is kept dark during growth to discourage algae and cyanobacteria; a clear container is used for viewing. [5]
His illustrated plants are G. hispidula. Applying that arrangement to barthlottii would be an experiment, not a verified species-specific recipe. In particular, the long-lived planting illustrated in that article cannot establish that this annual will persist for years. An observation setup should support the plant’s growth and flowering while avoiding repeated excavation of its delicate underground leaves.
Genome claims need the right species
The genus is famous for exceptionally small plant genomes, but that distinction should not be attached casually to G. barthlottii. Fleischmann and colleagues’ 2014 genome study explicitly identifies sampling of delicate annual species, including barthlottii, as deficient because enough plant material was difficult to obtain. [6]
Consequently, the paper does not support advertising this species with a smallest-genome claim borrowed from another Genlisea. The practical lesson is to retain the species and accession beside any numerical result. A measurement from a perennial relative cannot fill a missing measurement for a short-lived annual.
Conservation at a documented site
Couch and Cheek’s Mont Wokou important-plant-area assessment lists G. barthlottii among the site’s threatened plants, with a Vulnerable category in its table. The assessment describes granite quarrying on two sides of the inselberg as a substantial habitat threat and notes that botanical survey work was incomplete. [7] This is an attributed site-assessment record, not a newly checked global Red List determination.
It gives a concrete reason to care about the habitat as well as the individual species. Protecting a wet patch requires retaining the rock surface, water movement and surrounding vegetation that sustain it. Cultivated plants with documented origins can support observation and education, but they do not replace those natural communities. For a plant whose growing season is brief, surveys also need to coincide with the period when it can actually be found and identified.
Sources and further reading
- Kew: Genlisea barthlottii, accepted name, range and life form
- MNHN: holotype P00057042, Pobéguin 1358, August 1906
- Porembski, Fischer and Gemmel (1996): Genlisea barthlottii; identification key on page 154
- Fleischmann: doctoral synthesis, annual life history and section Africanae
- Brittnacher (2022): Grow Genlisea so you can see the traps
- Fleischmann and colleagues (2014): Genome sizes and chromosome numbers in Genlisea
- Couch and Cheek: Mont Wokou important plant area assessment
Sources checked 2 October 2026. Diagnostic photographs and final release review pending.
