The carnivorous plant encyclopedia - Chapter 3: plants for the expert: Heliamphora (Sun pitcher) - the gallant mesa dweller

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Heliamphora (Sun pitcher):

Habitat:
Although the genus Heliamphora is collectively known as "sun pitchers" (Greek:helios=sun) the correct term derivation actually stems from the Greek word helos, which means "marsh". Therefore, the more accurate name is "marsh pitchers". All Heliamphora species are exclusively endemic to the table-top mountains of the Gran Sabana in Venezuela, one of the most secluded places in the world, which stretches into parts of western Guyana and northern Brazil. The prevailing climate conditions in this region are fairly harsh, characterised by rapid changes in weather and an extremely high precipitation average, while temperatures between day and night can differ up to 20°C.

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Cultivation:
The genus Heliamphora is a real rarity in garden centers, yet if part of the carnivorous plant assortment then most likely in form of the subspecies Heliamphora minor (~10cm in height), Heliamphora nutans (~20cm in height) and Heliamphora heterodoxa (~30cm in height). Subspecies like the bright yellow Heterodoxa ionasii (~40cm in height, right image above) on the other hand are usually only available for sale on specific carnivorous plant online shops. Among carnivorous plant experts the Heliamphora is considered as one of the more challenging plants in cultivation, especially because the treacherous weather conditions atop the Venezuelan tepuis are very difficult to replicate in the terrarium microclimate. Vital year-round basics for all Heliamphora species are ample light exposure, warm day temperatures between 20-25°C opposed to rather cool night temperatures not higher than 15°C, at least 60% humidity and a low-nutrient soil (preferably sphagnum mixed with aggregates like perlites or quartz sand). They like moist soil but won’t tolerate waterlogging because otherwise their sensitive roots may rot, which is why in contrast to other pitcher plants the Heliamphora enjoys being watered from above. During winter fluorescent lamps are definitely recommended to compensate for potential lack of sunlight as much as possible. Without enough light, the pitcher coloration will fade, the cover leaf that is fused into the tube will shrink, and the shape of the pitcher will malform altogether.

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Trap mechanism:

While the Heliamphora do have the typical passive pitfall traps which lure prey, mostly ants, by way of glaring colorplay, nectar secretion and sweet scents, they have some unique distinctions opposed to most pitcher plants. Firstly, virtually all pitcher plants secrete alluring nectaries through their lid. The Heliamphora don't have this lid. Instead, atop their leaf they have a "nectar spoon" that is responsible for the production of these nectaries. Secondly, over the centuries the extremely erratic and high level of rainfall in the tepuis had the Heliamphora develop small slits in their tube which allow them to control the amount of rainwater inside the pitcher by draining off any excess rainwater when necessary. Lastly, carnivorous plants are scientifically defined as plants that attract, trap and kill prey on the one hand, produce their own digestive enzymes on the other. Yet the Heliamphora doesn't do the latter but relies on symbiotic bacteria to decompose prey. Hence, even though the Heliamphora is commonly listed as a carnivorous plant it is actually a protocarnivorous plant.

Much Love and Light,

Alex

Literature inspiration: Kosmos Garten: Fleischfressende Pflanzen