Rudgea pungens C. M. Taylor, Bruniera & Zappi 2015
Creators: name: Lachenaud, Olivier
name: Bruniera, Carla P.
name: Zappi, Daniela C.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Gentianales
Rubiaceae
Rudgea
Rudgea pungens

description: 7. Rudgea pungens (Steyermark) C.M. Taylor, Bruniera & Zappi (2015: 45, p. 4).
– Psychotria pungens Steyermark (1972: 677). (Fig. 7 D–F).
Type: — FRENCH GUIANA. Without locality, s.d., F. M. R. Leprieur 118 (holotype, P! [P00837150]; probable isotype (unnumbered collection), G! [G00418599, G00418600]).
Shrub 0.3–2 m tall, with nearly horizontal branches; twigs glabrous, 1–1.5 mm thick, soon covered with a pale strawcoloured bark. Stipules 8–16(–20) × 1–7 mm, glabrous, marcescent and soon corky, consisting of a narrow tubular sheath 5–9(–12) mm long (usually split at flower-bearing nodes) bearing 8–15 terminal linear appendages 3–8 mm long, and 5–7 dorsal linear appendages 0.5-3 mm long, forming a very short decurrent keel inserted 1–3 mm above the base of the stipule. Leaves opposite; petioles 0.2–0.6 cm long, glabrous; blades elliptic, 6.5–14.5(–16) × 1.8–4.5(–5.5) cm, acute or obtuse at base, gradually long-acuminate at apex, very thick, entirely glabrous, drying olive green to olive brown; midrib concave above; secondary veins 5–10 on each side of midrib, strongly ascending, forming an angle of 45–60° with the midrib; tertiary veins invisible in fresh leaves, sometimes slightly prominent when dry; domatia absent. Inflorescences terminal, subcapitate and involucrate, ca. 8-flowered, patent to sub-erect, glabrous, sessile or pedunculate; peduncle (when present) terete, to 1 cm long; flower-bearing portion 1.3–2.2 × 1.4–3.5 cm, secondary branches apparently absent or extremely reduced in flower, to 2 mm long in fruit; bracts pale green, numerous and imbricate in several rows, 10–20 × 2–7 mm, lanceolate, entire, acute at apex, glabrous or shortly ciliate, erect or patent, persistent in fruit. Flowers sessile, 5-merous, heterostylous. Hypanthium obovoid, 1.5 mm long, glabrous, Calyx tube 0.5–1 mm long, glabrous; lobes linear to narrowly triangular, 1.2–3.5 × 0.5–1 mm, glabrous or ciliate. Corolla white, tube narrow and almost cylindrical, 13 mm long, 1 mm wide at base, 1.5–2.5 mm wide at mouth, glabrous outside (inside not seen); lobes narrowly triangular, 2.5 × 1 mm, glabrous, with short, obtuse dorsal appendage 0.5 mm long. Stamens included in long-styled flowers, or exserted with filaments exceeding corolla throat by 1 mm in short-styled flowers; anthers 2.3 × 0.3 mm. Disk shortly cylindrical, 0.5 mm long, glabrous. Style exserted, exceeding corolla mouth by 1.5 mm in long-styled flowers, or included in short-styled flowers. Fruits ovoid with truncate apex, 11 × 7–8 mm when fresh, 7–10 × 5–7 mm when dry, dark red-brown and hard when immature, cherry red when mature, glabrous, sessile, crowned with persistent calyx 2.5–4 mm in diameter. Pyrenes plano-convex, hemi-obovoid to hemi-ellipsoid, 9 × 6.5 mm, dorsal side smooth, ventral side smooth. Seeds with a deep T-shaped ventral furrow.
Distribution and ecology: —This species is only known from French Guiana (Fig. 5), where it occurs on the main summits of the central Inini-Camopi chain (Mts Atachi Bacca to Mts Bakra) and disjunctly at low altitudes in the northeast; it should be expected in adjacent parts of Suriname and Brazil. It is apparently restricted to relatively low forests on rocky substrates, 5-800 m in elevation, and is locally abundant.
Phenology: —Flowering collections were made in January, May and August; fruiting collections in January, March–April (full-sized, but still hard) and August (mature fruits). As in the similar Rudgea billietiae, the fruits probably take several months to mature.
Notes: —This species, originally described in Psychotria (Steyermark 1972), was recently transferred to Rudgea (Taylor et al. 2015) but its affinities within the genus were still unclear. Taylor and Bruniera (2018) mentioned its similarity to the R. bracteata J.H. Kirkbride (1981: 97) group, especially because of the well-developed bracts, but members of that group have larger fruits, and stipules with a prominent dorsal keel and without marginal appendages. The involucrate inflorescences and narrowly tubular stipules of R. pungens are unusual characters in Rudgea, but the discovery of R. billietiae, with similar stipules and lax inflorescences, links it to R. cornigera, R. hostmanniana and R. tanaosepala, which have lax inflorescences and shorter stipular sheaths. The differences between these species are summarised in Table 1.
The original description of the species was based on a single specimen without fruits or corollas, and is therefore incomplete on several points. The species is now known from additional complete material, which allows to present here a full description; only the interior of the corolla tube cannot be described, because the flowers are too few for a dissection to be made. The dimensions in brackets refer to a vegetative collection (Granville 4002) from Mount Bakra, French Guiana, which has slightly larger leaves and stipules; though it almost certainly belongs to this species, confirmation with reproductive material from the same area would be reassuring.
Specimens Examined: — FRENCH GUIANA. Crique Kapiri – RN2, bassin de l’Approuague, 4°07’N, 52°05’W, 11 January 1991 (fallen fl.), G. Cremers 11474 (CAY); savane-roche [inselberg] Virginie, 4°11’N, 52°08’W, 18 February 2009 (fallen fl.), C. Delnatte, F. Billiet, J.- J. de Granville & B. Jadin 1682 (CAY); Fleuve Sinnamary, rive droite, layon ONF (n°7) direction Sud, à 7 km du fleuve, 1 May 1969 (fl.), J.- J. de Granville 128 (CAY); sommet des Monts Atachi Bacca, 4 March 1971 (fr.), J.- J. de Granville 765 (CAY, P); Monts Galbao, 10 km WSW Saül, 14 March 1973 (imm. fr.), J.- J. de Granville 1534 (CAY, P); Monts Bakra, versant Sud, 5 km WSW du pic Coudreau, 28 September 1980 (st.), J.- J. de Granville 4002 (CAY, P); Montagne Bellevue de l’Inini, zone centrale, 23 August 1985 (fl. & imm. fr.), J.- J. de Granville, L. Allorge, G. Cremers, A. R. A. Görts-van Rijn & J. F. Kodjoed 7770 (BR, CAY, P); Crique Gabaret, bassin de l’Oyapock, Saut Mérignan, 13 April 1988 (fallen fl.), J.- J. de Granville 10275 (CAY); Monts Atachi Bacca, versant Nord, 9 km au SE de Gobaya Soula, 3°33’N, 53°55’W, 12 January 1989 (fl.), J.- J. de Granville, G. Cremers, J. I. Hagemann, B. E. Leuenberger, R. W. Sanders & M. Sangrey 10616 (CAY, P); Monts Atachi Bacca, est du plateau sommital, 3°33’N, 53°55’W, 22 January 1989 (fr.), J.- J. de Granville, G. Cremers, J. I. Hagemann, B. E. Leuenberger, R. W. Sanders & M. Sangrey 10861 (CAY, P); layon Régina – Kaw, 4°21’W – 52°08’W, 7 August 1997 (fallen fl.), V. Hequet 688 (CAY); Route Régina – Saint Georges, piste de la savane-roche [inselberg] Virginie, 4°11’05”N, 52°08’13”W, 6 April 2014 (fr.), O. Lachenaud 1720 (BR, CAY, L, MO, P); without locality, s.d. (fl.), L.C.M. Richard s.n. (P [P04008549], mixed with R. billietiae); sommet nord du Mont Galbao, 29 January 1978 (fallen fl.), Tay 91 (MPU).
description: Published as part of Lachenaud, Olivier, Bruniera, Carla P. & Zappi, Daniela C., 2022, The Rudgea hostmanniana complex (Rubiaceae) in the Guiana Shield region, pp. 219-242 in Phytotaxa 561 (3) on pages 236-237, DOI: 10.11646/phytotaxa.561.3.1, http://zenodo.org/record/7069870