Nepenthes parvula G.W.Wilson & S.Venter, 2016

Wilson, Gary W. & Venter, Stephanus, 2016, Nepenthes parvula (Nepenthaceae), a new species from Cape York, Queensland, Australia, Phytotaxa 277 (2), pp. 199-204 : 200-202

Nepenthes parvula G.W.Wilson & S.Venter , sp. nov.

Type:— AUSTRALIA. Cape York, ‘Jardine Swamp’ , 11 ° 06′ 17.85″S, 142 ° 20′ 13.45″E, 20 m, female fl. 27 August 2012, Wilson & Venter 724 (holotype CNS! , isotype BRI! ).

Diagnosis:— Nepenthes parvula is similar to N. tenax from which it differs in having small aerial pitchers (35–60 × 10–15 mm), red colour of the upper surface of the lid on aerial pitchers, more dense nectar glands (250–300 per cm 2 vs. 100–150 per cm 2) on the abaxial surface of the pitcher lid, smaller male flower, much shorter mature fruit, and restriction to an ever-wet environment.

Description:— Erect subshrub 0.35(–0.50) m tall. Stems circular in cross section (diameter 2.5–5.0 mm), internodes 0.5–5.0 mm long at base and 2.0–10.0 mm near apex; indumentum tomentose with white-coloured simple hairs and dark-coloured stellate hairs. Lower leaves coriaceous, sessile, linear-lanceolate, 10–25 × 5–10 mm, slightly to moderately arched, apex attenuate-acute, base contracting gradually towards the petiole, clasping the stem for 2/3 of its circumference, margin sparsely fimbriate; longitudinal nerves 4–6 per side, evenly spaced; pennate nerves rectangular with longitudinal nerves. Tendril straight, 5–10 mm long, about 0.8 mm in diameter, insertion simple; indumentum as stem. Upper leaves coriaceous, sessile, linear-lanceolate, 30–90 × 7–14 mm, moderately arched, Vshaped in cross section, apex attenuate-acute, base contracting gradually towards the petiole, clasping the stem for 2/3 of its circumference, margin entire (rarely slightly fimbriate); longitudinal nerves 3–4 on each side of the midrib, on outer 3/5 of blade, pennate nerves rectangular with longitudinal nerves, except between the outermost nerve and margin where they are at 45°. Tendril kinked (sometimes coiled) 30–60 mm long, 0.8–1.0 mm diam., insertion simple; indumentum as stem. Lower pitchers ovoid, 15–30 × 5–10 mm, constriction below midpoint, nectar gland density 900–1200 per cm 2; alae extend length of pitcher but reducing towards the base, fimbriate in upper portion, fimbriae 0.4–1.2 mm long; mouth oblique and subovate; peristome subcylindrical to slightly flattened, 0.4–1.2 mm broad, ribs 0.05–0.2 mm apart, 0.05–0.10 mm high, outer margin entire, revolute, inner margin dentate, teeth slightly curved; lid sub-orbicular, 5–14 × 3.2–13.0 mm, flat, no appendage, apex rounded; crateriform glands evenly distributed; spur straight, simple (sometimes bifurcate or multiple), 1.0– 3.5 mm long. Upper pitchers cylindrical, 35–60 × 10–15 mm, constriction below midpoint, nectar gland density 1200–1500 per cm 2; alae reduced to ridges with an entire margin, 0.1–0.3 mm wide; mouth oblique and subovate; peristome subcylindrical to slightly flattened, 1–2 mm broad, ribs 0.15–0.4 mm apart, 0.05–0.15 mm high, outer margin entire, revolute, inner margin dentate, teeth slightly curved, 0.1 mm long; lid sub-orbicular, 10–20 × 10–15 mm, vaulted, lower surface consistently deep red in colour, no appendage, apex rounded (sometimes slightly indented); crateriform glands evenly distributed, 250–300 per cm 2, suborbicular 0.15- 0.20 mm, with a thin marginal rim; spur straight, simple (sometimes bifurcate), 2.5–6.0 mm long. Male inflorescence a raceme, up to 100 mm long, peduncle 25–50 mm long; bracts absent; rhachis 25–50 mm long, indumentum dense except on adaxial surface of tepals and staminal column, hairs simple, white; up to 50 flowers, 1(–3)-flowered, pedicel 2.5–5.0 mm long, no bracteole; tepals 2.0–3.5 × 1.0– 2.5 mm, nectar glands on red-coloured adaxial surface of tepals; staminal column 0.8–1.3 mm long, anther-head about 1.5 mm in diameter. Female inflorescence up to 100 mm long, peduncle 40–60 mm long, bracts absent; rhachis 40–60 mm long; up to 35 flowers, partial-peduncle 1-flowered, 3-locular, pedicel 2.5–5.0 mm long, no bracteoles; tepals 2.5–3.0 × 1.5 mm, nectar glands on red-coloured adaxial surface of tepals, indumentum dense except on adaxial surface of tepals and stigma surface, hairs simple, white; capsule 3.5–6.0 mm long and seeds 2.7–3.5 mm long.

Etymology:—The epithet parvula refers to the small size of mature plants.

Phenology: Plants of Nepenthes parvula and N. tenax grown in identical conditions at the Australian Tropical Herbarium in Cairns maintained the characteristics described here and in Clarke & Kruger (2006). However, in contrast with N. tenax , N. parvula shows a marked susceptibility to cooler temperatures and plants at CNS in the lowland tropics of North Queensland either die or die back in the Dry Season when overnight temperatures drop to 10‒12 ° C. This response had previously been noted by other workers, e.g. C. Clarke pers comm. in 2013, P. Lavarack pers comm. in 2014, A. Field pers comm. in 2014.

Distribution and ecology:— Nepenthes parvula occur in Queensland, Cape York only growing on freshwater swamps in the lower Jardine River catchment, at 0–30 m a.s.l. The surveys by us show N. parvula is restricted to Regional Ecosystem 3.3.64a “ Palustrine wetland (e.g. vegetated swamp) ” ( Queensland Herbarium 2015). The surveys also show that the other three species of Nepenthes occur, although rarely (i.e. N. mirabilis , N. tenax and N. rowaniae ) ( Fig. 2 ). This ecosystem does not burn in the wildfires that irregularly but not infrequently sweep across the landscape and as result N. parvula is characterised by a retained “skirt” of lower pitchers (refer Fig. 3B ). Plants of N. parvula were in flower or had mature fruit dehiscing seed when the type was collected in September 2012.

Conservation status:—The compact nature of mature plants and small size of the aerial pitchers of N. parvula make it desirable to collectors. Illegal collections of both seed and plants occur (S. Templeton, pers comm. August 2013, A. Field, pers comm. May 2015). Damage by feral pigs (pers obs. 2012, 2013, and 2015) is an ongoing concern. Field surveys indicate that the EOO is ≤ 20 km 2, the AOO is ≤ 5 km 2, and the number of plants is more than 5000. However, due to difficulties in accessing much of the potential habitat and working in peat swamps inhabited by Estuarine Crocodiles ( Crocodylus porosus Schneider, 1801 ), determining exact values is difficult and our values are conservative. We propose a Conservation Status of Vulnerable under the criterion B1a+B2a of IUCN (2015).

Additional material examined:— AUSTRALIA, Queensland, Jardine Swamp , 11 ° 06′ 17.85″S, 142 ° 20′ 13.452″E, 27 August 2012, ibidem Wilson & Venter 713 (♀) ( CNS-137416 ) , ibidem Wilson & Venter 714 (♀) ( CNS.137417 ), ibidem Wilson & Venter 715 (♀) ( CNS-137418 ) , ibidem Wilson & Venter 716 (♀) ( CNS-137419 ) , ibidem Wilson & Venter 72 0 (♂) ( CNS-138853 ) , ibidem Wilson & Venter 721 (♂) ( CNS-138854 ) , ibidem Wilson & Venter 722 (♂) (CNS-138855) , ibidem Wilson & Venter 723 (♀) ( CNS-138856 ) , ibidem Wilson & Venter 724 (♀) ( CNS-138857 ) ; Wilson & Venter 745 (♂) ( CNS-140326 ) AUSTRALIA, Queensland, Jardine Swamp , 11 ° 06’ 08”S 142° 20’ 10”E, 25 July; Wilson & Venter 746 ( CNS-134394 ) ; Queensland, Packsaddle Creek 11° 04′ 50″S, 142° 25′ 07″E, 27 July 2013 , 2 km South of the Usher Point Road , Heathlands Resources Reserve , Cape York .

Figures

FIGURE 2. The habitat association of four species of Nepenthes in the eight transects at Jardine Swamp Cape York, Queensland (data summed for analysis). Type 1: Dry Acacia-dominated with Melaleuca sp. Shrubland or Low Woodland with scattered Hakea pedunculata, Banksia dentata and Asteromyrtus lysicephala on siliceous sands on sand sheets and slight rises; Type 2: Seasonally inundated ecotone with scattered Hakea pedunculata and Asteromyrtus lysicephala with Baloskion tetraphyllum and herb species (often carnivorous) on siliceous sands. Type 3: Permanently moist/inundated swamp with water pH~5 dominated by forbs, herb species, (often carnivorous), and dwarf Asteromytus lysicephala on a variable peat layer on a siliceous sand substrate. Type 4: Permanently moist/inundated swamp dominated by Ghania sp. ±Hanguana malayana, on a variable peat layer on a siliceous sand substrate—slightly (10–20 mm) elevated above 3.

FIGURE 3. Nepenthes parvula A habit with upper pitchers; B male plant with inflorescence with receptive flowers (l) and opened flowers (r); C female inflorescence; D male inflorescence. Images by S. Venter.