Piper caguanense 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 : 267-270

Piper caguanense W. Trujillo-C. & M.A.Jaram . sp. nov., Figs. 2 , 3 , 4 .

Type:— COLOMBIA: Caquetá, San Vicente del Caguán, road to Neiva , trail to Las Morras , 1031 m, 2°26’30”N, 74°47’2”W, 4 January 2011 [fr], W . Trujillo-C. & M. Calderón 1812 (holotype COAH!, isotype HUA!) .

Diagnosis:— Piper caguanense differs from the morphologically similar P. miguel-conejoanum Trel. & Yunck. (1950: 287) by the scabrous leaves with evident idioblasts vs. smooth leaves without evident idioblasts in P. miguel-conejoanum .

Shrub, 1.5 m tall. Internodes 5–9 cm, smooth, reddish, pubescent, with evident idioblasts throughout the plant except on the connective of the anthers. Prophylls 1.8–2.2 cm, green, pubescent, caducous. Petioles uniform in shape and size along axes, 0.5–1 cm long, vaginate at the base, smooth, pubescent. Leaf blades coriaceous, dark green above, fresh green below, brown when dry, uniform in shape and size along axes, 12–17 cm × 5.5–8.8 cm, ovate, blade medially symmetric, base rounded, equilateral, insertion asymmetric; leaf blade pubescent on both surfaces with trichomes (1–) 1.5–2 mm, scabrous above, ciliate; pinnately nerved from the lower half of the midvein; secondary veins 4–5 pairs, eucamptodromous, with spacing decreasing and angle increasing towards the base; tertiary veins percurrent; apex acuminate. Inflorescences and infructescences simple spikes, terminal, erect; peduncles 4–4.5 cm long, pubescent, green; fruiting rachis 7–9 cm × 0.2 cm, fruits densely grouped along the rachis. Floral bracts cucullate, triangular when seen from above, 0.3–0.5 × 0.3– 0.3 mm, glabrous on the adaxial surface, margin fimbriated, forming bands around the spike. Flowers with three stamens, filaments 0.3–0.5 mm long, anthers 0.15–0.35 × 0.1–0.3 mm long, longitudinally dehiscent, with two thecae, with connective not protruding, glabrate, idioblasts not evident; stigmas 3, 0.05–0.2 mm long, sessile. Fruits rectangular in lateral view, laterally compressed, green when fresh and brown when dry, 0.8–1.2 × 1.2–1.5 mm, glabrous, partially immersed in the rachis, with stigmas persistent 0.05–0.2 mm long, sessile. Seeds rectangular, laterally compressed, yellow.

Distribution:— Piper caguanense is endemic to the eastern slopes of the Andes towards the Amazonas basin in Colombia at 600–1200 m elevation in Tropical premontane wet forests (TPwf).

Habitat and ecology:— Piper caguanense is a shade-loving species growing in the understory of well-preserved and secondary forests.

Phenology:—Flowering samples were collected in March. Fruiting specimens were collected in October, January, and February.

Etymology:—The species is named for the type locality at San Vicente del Caguán, in Caquetá where the Caguán river is born.

Conservation status:— This species is known from four specimens representing two subpopulations. The locations where it occurs are threatened by deforestation and expansion of the agricultural frontier. The area of occupancy ( AOO) is 8 km 2 which is small and together with the continuing decline in quality of habitat, suggests that this new species is Critically Endangered [ CR B2 a] .

Comments:— Piper caguanense exhibits the traits of the Radula clade which has leaves that are pinnately nerved from the lower half of the midvein and spikes with bracts forming bands around the rachis ( Jaramillo et al. 2008). After several intents we were not able to obtain ITS sequences for this species, thus, molecular evidence is lacking to confirm its phylogenetic position. Piper caguanense and P. miguel-conejoanum are both villous shrubs with long peduncles but Piper caguanense has scabrous leaves with evident idioblasts whereas P. miguel-conejoanum has smooth leaves without evident idioblasts.

Additional specimens examined:— COLOMBIA: Caquetá, Florencia, trail to Sucre , 1076 m, 1°47’50”N, 75°38’50”W, 18 October 2020, W . Trujillo & F . Hoyos 4123 ( COAH!); same locality, 12 December 2020, W . Trujillo et al. 4133 ( COAH!); same locality, 24 September 2020, F . Hoyos & W . Trujillo 039 ( COAH!) .

Figures

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

FIGURE 3. Piper caguanense. A. Sympodial branch. B. Detail of infructescence. C. Floral bract lateral view. D. Floral bract view from above. E.Anthers. F. Fruit lateral view. G. Floral diagram. Illustration by Marcela Morales based on the type W. Trujillo-C. & M. Calderón 1812 (COAH).

FIGURE 4. Piper caguanense. A. Sympodial branch; adaxial and abaxial leaf surfaces and a spike. B. Detail of the leaf base and prophyll. C. Sympodial branch; adaxial and abaxial leaf surfaces and pubescent spikes and internodes. Photos by W. Trujillo from W. Trujillo 4133 (COAH).