Heliamphora elongata — Vorstman's Guide to the Carnivorous Plants

No photograph of this species under a Creative Commons licence or in the public domain is in the guide yet.

Identification

A rosette of erect pitchers, each formed from a single leaf grown shut into a funnel with a seam down the front. The character the epithet refers to is a proportion: the pitchers are narrow and elongated relative to their width, giving the plant a slimmer, more upright silhouette than most species of the genus, which read rather as broad funnels. On the back rim sits the nectar spoon, the small hooded organ that in Heliamphora has replaced the broad hood of Sarracenia. Colour runs from yellow-green in shaded plants to red and red-brown in plants in full light; older pitchers often colour up more strongly than young ones. The inflorescence is a one-sided raceme on a long, erect scape that rises well above the rosette, with nodding flowers whose tepals change colour and stiffen as flowering proceeds.

Similar species

On the eastern tepuis this species is not alone. Heliamphora nutans, the first species of the genus to be described, occurs on the same chain and has broader, less elongated pitchers with a wide drainage pore. Heliamphora ionasi, which grows in the valley between Ilú and Tramen, is one of the largest species of the genus and separable at a distance: its pitchers are massive and strongly bellied, where those of elongata stay narrow. Between those two a natural hybrid is known besides, intermediate in size and shape — reason not to attach a name too quickly down in the valley. Confusion with Sarracenia is ruled out geographically, and structurally too: the broad hood over the mouth is entirely absent here.

The trap and how it works

A pitfall trap, with the division of labour that holds for the whole genus. The plant produces little or no digestive enzyme of its own; bacteria and other micro-organisms in the pitcher fluid break the prey down, after which the plant takes up the nitrogen and phosphorus compounds released. The nectar spoon on the back rim is the lure: nectar is secreted there, and an insect coming to it already stands over the opening. The upper zone of the inner wall bears downward-pointing hairs up which climbing back is impossible; below that the wall is smooth, so a prey animal that once starts to slide does not stop. A drainage slit in the wall keeps the fluid level constant. The elongated form means a relatively deep trap with a small opening — proportionally less catching surface, but also less loss in heavy rain.

Habitat and ecology

The summit plateau of the table mountain (R4): bare sandstone with fissures, basins and hollows in which acid peat collects, with no soil in the ordinary sense. Within it the plant grows mainly on the wet ground with bog moss (W1), where water stands or seeps slowly through, and further on the slopes around the summits, where organic matter has accumulated in ledges and crevices. The substrate is extremely poor in nitrogen and phosphorus and is continuously leached by the unremitting rain. The climate is cool and all but permanently wet: the plateaus lie in cloud for much of the day, the nights are cold, and the seasons are barely noticeable.

Distribution and elevation

Endemic to Bolívar state, Venezuela, on the Ilú–Tramen massif and the adjoining Karaurín-tepui, all three part of the eastern tepui chain. The species grows both on the summits and on the surrounding slopes, roughly between 1800 and 2600 m. The genus as a whole is confined to the table mountains of the Guiana Shield — Venezuela, western Guyana and the far north of Brazil — and the eastern chain shows the pattern well: mountains that lie close together on the map sometimes share a species and sometimes each have their own, depending on how long ago the plateaus were cut apart. For a bog plant the rainforest below is as hard a barrier as sea water.

Recorded (one-degree cells)

Distribution based solely on records at GBIF (Global Biodiversity Information Facility), not on TDWG regions — those are often far larger than the actual range. The light halo is the area around a record, the dark core the record itself. The darker cells are 2 one-degree squares — roughly a hundred and ten kilometres — in which the species has been recorded, from all GBIF records. This is coarser than for most species because hardly any record of this plant carries an accurate coordinate: the locality of poached species is obscured at source. At this scale that obscuring disappears into the noise. The cells show where it has been seen, not where it occurs: an empty square means nothing.

Forms and variation

No varieties or subspecies have been described. There is clear variation in pitcher length and in the waviness of the pitcher rim between plants from different mountains and even within a single population, alongside the usual colour variation between green plants in shelter and red ones in full light; neither has been fixed with a name. In the valley between Ilú and Tramen a natural hybrid with Heliamphora ionasi occurs, where the two species meet. Such crosses are no rarity in this genus and are in the field the largest source of doubt when putting a name to a plant.

Where and when to see it

The massif lies in the far east of Bolívar, near the better-known Roraima route, but is itself far less visited; the climb takes days and is made with a guide from the region. Look for the species on the wet, open parts of the plateau and on the ledges of the slopes around it. Judge the plant on the ratio of pitcher length to width, not on absolute size: young pitchers of a broad species can look narrow, but stay proportionally shorter. If you descend into the valley between the two mountains, reckon with crosses with the much larger Heliamphora ionasi. Nothing about the flowering period is established in the literature.

Conservation status

The species has not been assessed for the IUCN Red List, and there is no CITES listing: Heliamphora appears in no appendix. What is known: the distribution covers two neighbouring massifs, and within them both the summits and the slopes, which by the standards of this genus is a reasonably wide area; several populations are large. The area lies in protected territory and can be entered only with a permit and a guide, and there is no agricultural or mining pressure of consequence. Lying near a well-known tourist route does mean these mountains are less untouchable than the remote massifs further south. Collection for trade counts as the risk for the genus, but material in cultivation comes almost entirely from seed and tissue culture. The absence of a formal assessment here reflects the research backlog in the Pantepui region, not an established decline.

Scientific name

Heliamphora elongata | Nerz, 2004

Described by Joachim Nerz in 2004, in Carnivorous Plant Newsletter 33(4): 111–116. The type area lies on the Ilú-Tramen massif in Venezuela, specifically on Ilú-tepui. The species name elongata is Latin for "elongated" and refers to the pitchers' drawn-out shape.

World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.