Heliamphora hispida — Vorstman's Guide to the Carnivorous Plants

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 that gave the species its name is on the outside: the pitchers are densely set with stiff, bristly hairs, which is what hispidus, rough-haired, refers to. In good light that indumentum gives the plant a matt, felted look instead of the glossy one most relatives have, and against the light a fine fringe of hairs stands out against the sky. On the back rim sits the nectar spoon, the small organ that in Heliamphora takes the place of the broad hood Sarracenia carries. The pitcher wall widens towards the top, and the colour runs from yellow-green in sheltered plants to red in plants in full light. The inflorescence is a one-sided raceme on a long scape, with nodding flowers of usually four tepals that change colour and stiffen as flowering proceeds.

Similar species

Cerro de la Neblina holds several species of the genus, so identifying by the name of the mountain alone does not work here. Heliamphora neblinae, of the same massif, is considerably larger and lacks the dense bristly covering of the outer wall. Heliamphora tatei and its relatives in that group can be separated in the field from a distance, because they form a true woody stem and so do not stay as a flat rosette on the ground; hispida is and remains a rosette plant. Heliamphora parva of the same region is smaller and differently haired. If need be, run a finger along the outer wall: the stiff, bristly hairs of this species can be told by touch from the soft, woolly down found in some relatives. Confusion with Sarracenia is ruled out geographically.

The trap and how it works

A pitfall trap. The plant produces little or no digestive enzyme of its own; 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 stands directly over the opening. The upper zone of the inner wall bears downward-pointing hairs, so an attempt to walk back up fails; below that the wall is smooth. A drainage slit holds the fluid level steady. The dense indumentum on the outside has nothing to do with capture; in plants from such altitudes, hairiness is usually linked to fierce insolation and strong radiative cooling at night, but for this species that has not been investigated.

Habitat and ecology

The summit plateau of the table mountain (R4): a landscape of bare sandstone, fissures and basins 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. The substrate is extremely poor in nitrogen and phosphorus and is continuously leached by the unremitting rain. The climate on Neblina is wet and cool even by tepui standards: the mountain owes its name to the cloud that hangs around it almost permanently, and near the summits it freezes at times overnight. The species grows up into that highest, most meagre zone and is thus the Heliamphora that reaches furthest up.

Distribution and elevation

Endemic to the massif of Cerro de la Neblina, on the border of Amazonas state in Venezuela and Amazonas state in Brazil, and within it confined to the southern part of the plateau, around the highest summits. Sites lie roughly between 1800 and nearly 3000 m; no other species of the genus has been found so high. The genus as a whole is confined to the table mountains of the Guiana Shield, in Venezuela, western Guyana and the far north of Brazil, and Neblina is its southern outpost: the mountain lies far from the eastern tepuis and has a small set of species of its own that occur nowhere else.

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 square is the only one-degree cell — 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. It shows where the species has been seen, not where it occurs: an empty square means nothing.

Forms and variation

No varieties or subspecies have been described. There is variation in the density and length of the indumentum and in the colour of the pitchers, which runs from yellow-green to red according to exposure; neither has been fixed with a name. Natural hybrids with the other species of Neblina are not documented, although those species grow on the same massif. That may be a matter of habitat — hispida occupies the highest ground — but may equally reflect the very low intensity of fieldwork: the Neblina plateau is among the least visited places on the continent.

Where and when to see it

This is the hardest species of the genus to reach. The massif lies in protected border country that may be entered only with a permit on either side, and the climb takes days. Anyone who gets there will recognise the plant most quickly by the matt, felted outside of the pitcher: do not stroke it, but look at it both with the sun behind you and against the light, because it is backlighting that makes the bristles glow as a silver fringe. Note too the growth form of whatever stands beside it — a plant with an obvious stem is not hispida. The flowering period of the species is not 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 is that the distribution is confined to a single massif and within it to the high southern part — a small area, and so vulnerable to any change occurring there, including a shift in the cloud base under a changing climate, which is regarded as the most realistic risk for high-altitude tepui plants. Against that, Neblina lies in a national park on both sides of the border, visits require a permit, and the remoteness rules out almost every form of pressure. Collection for trade hardly comes into it here; material in cultivation comes from seed and tissue culture. The absence of an assessment reflects the research backlog, not an established decline.

Scientific name

Heliamphora hispida | Wistuba & Nerz, 2000

Described by Andreas Wistuba and Joachim Nerz in 2000, in Carnivorous Plant Newsletter 29(2): 37–41. The type area lies on Cerro Neblina, the southernmost tepui of the Guiana Highlands, on the Brazil-Venezuela border. The species name hispida is Latin for "bristly, roughly hairy" and refers to the plant's densely hairy surface — the opposite of the hairless H. glabra.

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