Piper rubrifolium W. Trujillo-C. & M.A.Jaram

Trujillo, William, Jaramillo, M. Alejandra, Toro, Diego & Balslev, Henrik, 2023, Over- and under-described: new species, new synonyms, and a new name in the megadiverse genus Piper (Piperaceae) on the east Andean slopes, Phytotaxa 601 (3), pp. 263-284 : 276-279

Piper rubrifolium W. Trujillo-C. & M.A.Jaram . sp. nov., Figs. 1 , 2 , 9 , 10 .

Type:— COLOMBIA: Caquetá, Florencia, trail to Tarqui, La Ruidosa ravine, 1°52’8”N, 75°39’40”W, 2027 m, 16 July 2014 [fr], W . Trujillo et al. 3139 (holotype COAH!].

Diagnosis:— Piper rubrifolium is closely related P.sabaletasanum Trel. &Yunck.(1950: 104) , P.spoliatum (1950: 118) and P. cajambrense . It differs from P. cajambrense and P. spoliatum in having smooth internodes and petioles (vs. internodes and petioles with epidermal warty outgrowths in the latter). It can also be easily differentiated from P. sabaletasanum by its smooth leaves vs. bullate leaves in the latter. Piper rubrifolium has young leaves that are red on the underside, another trait that characterizes this species.

Shrub to 4 m tall. Internodes smooth, green to red, glabrous to puberulent, idioblasts not evident in any part of the plant. Prophylls lacking. Petioles uniform in shape and size along all axes, 4–6 cm long, vaginate along their entire length, smooth, glabrous to puberulent, green to burgundy colored. Leaf blades chartaceous, brown when dry and red when fresh on the underside in young leaves, 12.5–16 × 29–37 cm, variable in shape along axes; on monopodial axes, blade ovate, medially symmetric, base lobate, with lobes 1–1.5 cm long, symmetric, and not overlapping the petiole, sinus open, equilateral, basal insertion symmetric; on sympodial axes, blade elliptic, medially symmetric, base auriculate, lobes asymmetric, the shorter lobe 0.7–3 cm long, the other lobe 2–2.2 cm longer, the longer one partially overlapping the petiole, sinus closed, inequilateral, insertion symmetric; leaf blade smooth, glabrous to puberulent on the abaxial surface, eciliate; pinnately nerved from the lower half to 3/4 of the midvein; secondary veins 4–5 pairs, festooned brochidodromous, with spacing decreasing and angle increasing towards the base; tertiary veins randomly reticulate to percurrent; apex acuminate. Inflorescences and infructescences simple spikes, terminal, erect; peduncles 3–4 cm long, glabrous, green; flowering rachis 9–14 cm and fruiting rachis 25–28 cm long, fruits densely grouped along the rachis. Floral bracts cucullate, triangular when seen from above, 0.6–0.8 × 0.3–0.5 mm, glabrous on the adaxial surface and margin, not forming bands around the spike. Flowers with four stamens, filaments 0.8–1.2 mm long, anthers 0.10–0.16 × 0.08–0.12 mm, longitudinal dehiscent, with two thecae, with connective not protruding, glabrate; stigmas 3, 0.03–0.07 mm long, sessile. Fruits one-seeded berries, globose, 2–4 × 1.8–4 mm, glabrous, partially immersed in the rachis, with stigmas persistent, 0.03–0.07 mm long, sessile, green when alive and black when dry. Seeds ovoid, dark brown.

Distribution:— Piper rubrifolium is endemic to the eastern cordillera of the Andes along the slopes towards the Amazon basin at 1500–2000 m elevation, in the Tropical montane rain forest (TMrf).

Habitat and ecology:—It is a shade-loving species growing in the understory of rainforests.

Phenology:—Flowering and fruiting specimen were collected in July.

Etymology:—The name Piper rubrifolium is derived from the Latin rubrum meaning red and folia meaning leaves, referring to burgundy color underneath on young leaves.

Conservation status:— This species is known from three specimens representing two populations. Its habitat is threatened by deforestation and expansion of the agricultural frontier. The extent of occurrence ( EOO) is 398 km 2 and its area of occupancy ( AOO) is 12 km 2, which, together with the continuing decline in quality of the habitat, suggests that it is Endangered [EN B1 a+ B2 a] .

Phylogenetic relationships:— Piper rubrifolium belongs to the Macrostachys clade ( Jaramillo et al. 2008). In our phylogeny this species forms a monophyletic group with taxa known to occur in the Chocó region, i.e., P. spoliatum , P. sabaletasanum , and P. cajambrense ( Figure 1 ).

Comments:— Piper rubrifolium is red on the abaxial surface of immature leaves and mature petioles, the petioles and internodes are smooth without epidermal warty outgrowths, and the leaf base has short lobes which are the most important characteristics that separate Piper rubrifolium from similar species.

Key to Piper rubrifolium and related species in the Macrostachys clade

1. Leaves bullate........................................................................................................................................................... P. sabaletasanum

– Leaves smooth....................................................................................................................................................................................2

2. Petioles with epidermal warty outgrowths .........................................................................................................................................3

– Petioles smooth (without epidermal warty outgrowths)................................................................................................ P. rubrifolium

3. Leaves oblanceolate, narrowed to the base ...................................................................................................................... P. spoliatum

– Leaves broad–elliptic, wide at the base....................................................................................................................... P. cajambrense

Additional specimens examined:— COLOMBIA: Caquetá, Florencia , trail to Campo Hermoso Alto , 3rd tunnel, 1°44’56”N, 75°44’36”W, 2037 m, 19 March 2020 [sterile], W. Trujillo & L. Sandoval 4029 ( UMNG-H!) . Putumayo, Mocoa, road Sibundoy-Mocoa at El Mirador , 1°04’11”N, 76°44’41”W, 2000 m, 9 July 1998 [fl], H. Mendoza & F. Quevedo 6035 ( HUAZ!) .

Figures

FIGURE 1. Phylogenetic relationships of the species Piper oteguanum, P. rubrifolium, P. laperdizense, P. calanyanum and P. morelianum based on Maximum Likelihood analysis of nrITS sequences. Names with taxonomic novelties are shown in bold. Names of clades follow Jaramillo et al. (2008), and Callejas-Posada (2020). Numbers above branches are ML bootstrap support values (>80).

FIGURE 2. The localities of four new Piper species on the east Andes slopes of Colombia, and Ecuador.

FIGURE 9. Piper rubrifolium. A. Sympodial branch with a spike near the apex. B. Fruit lateral view. C. Detail of the infructescence. D. Floral bract from above. E. Floral diagram. Illustration by Marcela Morales based on the type specimen, W. Trujillo et al. 3139 (COAH).

FIGURE 10. Piper rubrifolium. A. Sympodial branch showing abaxial and adaxial leaf surfaces. B. Abaxial and adaxial leaf surfaces, petioles and a young spike. C. Fruiting spike. Photos by William Trujillo from the type, W. Trujillo 3139 (COAH).