Aristolochia guillermoi F. González & B. Esquerre, 2025

Aristolochia guillermoi F. González & B. Esquerre , sp. nov.

Type:— PERU: Piura: Huancabamba: Route Puente El Silencio-Limón de Porcuya , before the town, 5°53'37"S, 79°31'51"W, 1240 m, 31 May 2025 (fl, fr), B. Esquerre 300 ( holotype: HUT!; GoogleMaps isotype: PRG!). GoogleMaps Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 .

Diagnosis:— Aristolochia guillermoi is similar to A. andina , from which it differs mainly by its glaucous leaves with densely reticulate venation beneath; its flowers with utricle 13–15 × 12–13 mm, syrinx 1.5–2 mm long, tube 16–24 mm long, and limb widely ovate, 8–14 mm long; its capsules 35–44 × 15–20 mm; and its seeds 5–6 × 5–6 mm, wingless and adaxially smooth ( versus leaves not glaucous beneath, with loosely arranged, inconspicuous venation beneath; flowers with utricle 8–12 × 4–5 mm, syrinx ca. 0.5 mm long, tube 6–12 mm long, and limb ovate, 14–20 mm long; capsules ca. 30 × 12–15 mm; and seeds 4–5 × 4–5 mm, with a vestigial wing ca. 0.5 mm wide, and adaxially warty in A. andina ).

Herbaceous vines with densely villous indument, the trichomes branched on stems, leaves, flowers and capsules; tubers not seen. Leaves with petiole 3–6 cm long, densely villous with branched trichomes; leaf lamina ovate, (7–)10–15 × (4–) 5–7 cm, chartaceous, upper surface light green, lower surface glaucous, base deeply cordate, lobes convergent to overlapping, sinuses 1.6–2 cm in depth, basal veins 5, prominulous and scarcely villous above, prominent and densely villous especially along the veins beneath, higher order veins densely reticulate, apex obtuse with a minute mucro at its tip. Pseudostipules present, triangular, 3–4 × 2–2.5 mm, folded, not expanded, accrescent or clasping. Pedicel plus ovary 4–5 cm long, densely villous, with branched trichomes, ebracteolate. Perianth densely villous outside, with branched trichomes, pale green, suffused purple along the main veins and in the limb, with unbranched, rigid conical trichomes inside the tube and the proximal portion of the limb; utricle oblong to obovoid, 1.3–1.5 cm long, 1.2–1.3 cm in diameter, syrinx asymmetric, 1.5–2 mm long; tube infundibular, 1.6–2.4 cm long, 4–5 mm proximal diameter, 1–1.4 cm distal diameter, forming an angle of approximately 90° with respect to the utricle; limb widely ovate, 0.8–1.4 × 0.8–1.2 cm, forming an angle of approximately 180° with respect to the tube, base round, apex obtuse, emarginate. Gynostemium 6-lobed, 3–4 × 3–4 mm. Capsule 6-carpellate, cylindrical, 3.5–4.4 cm long (including a rostrum of 6–8 mm long), 1.5–2 cm in diameter, basipetally dehiscent, septa entire. Seeds deltoid-triangular, 5–6 × 5–6 mm, black, flattened, adaxial surface smooth, raphe lineariform, expanded in a membranous extension almost as large as the proper seed, abaxial surface and margin scattered warty, wing lacking.

Phenology: — Aristolochia guillermoi has been observed with flowers in January to June, and with capsules in June to August.

Distribution, ecology and conservation status:— Aristolochia guillermoi grows in seasonally dry forests, at elevations between approximately 1000 and 1600 m, in the Department of Piura, Peru. The species has been observed flowering during the first six months of the year and setting capsules from June to August, a period during which vegetation dries out until rainfall begins in December or at the beginning of the following year. So far, this new species has only been observed growing in remnants of seasonally dry tropical forest on the mountain slopes along the Fernando Belaúnde Terry Highway, at elevations above 1000 m, between Puente El Silencio and Limón de Porcuya, in the Huarmaca District, Huancabamba Province, Piura Department within the Olmos river basin on the western slopes of the Andes ( Fig. 3 View FIGURE 3 ). Loss of natural habitat in the area is severe, both due to migratory agriculture and uncontrolled colonization. Despite this, the region has not received any protection from the Peruvian State, even though it is an area of endemism within the Amotape-Huancabamba Zone in northern Peru ( Weigend, 2002)—the type locality of, for example, Ficus jacobii Vásquez Ávila (1986: 201) , Passiflora santos-llatasii Esquerre (2019: 4) , Tropaeolum fintelmannii var. olmosense (Mansf.) Sparre (1973: 16) and Sobralia aryaelizabethiana Ocupa (2025: 10) . Until further exploration is conducted in Huarmaca District and surrounding areas, we have placed this new species in category DD (Data Deficient), according to IUCN guidelines ( IUCN 2024).

Etymology: —The specific epithet of the new species honors PhD. Guillermo Eduardo Delgado Paredes (deceased), a Peruvian biologist and researcher of the Universidad Nacional Pedro Ruiz Gallo. In recent years, he motivated the junior author to collect and cultivate this unusual Aristolochia , which turned out to be a new species. We dedicate this new taxon to him in recognition of his important work on conservation of plants from the seasonally dry tropical forests of northern Peru.

Additional specimens examined: — PERU. Piura: Huancabamba: Fernando Belaúnde Terry highway, Pte. El Silencio-Limón sector, near Limón de Porcuya , 1400 m, 05°52'43.66"S, 079°31'17.95"W, 31 May 2025 (fl), B. Esquerre 301 ( PRG) GoogleMaps ; entrance to Limón de Porcuya , 1590 m, 05°53'6.15"S, 079°32'11.89"W, 31 May 2025 (fl), B. Esquerre 302 ( PRG) GoogleMaps ; near Restaurante Las Gemelas , 1325 m, 05°53'5.88"S, 079°31'39.47"W, 01 June 2025 (fl, fr), B. Esquerre 303 ( PRG) GoogleMaps ; entrance to Limón de Porcuya , 1580 m, 05°53'6.10"S, 079°32'5.10"W, 04 June 2025 (fr), B. Esquerre 304 ( PRG) GoogleMaps ; near La Beatita , 1032 m, 05°55'2.51"S, 079°32'26.34"W, 04 June 2024 (fr), B. Esquerre 305 ( PRG) GoogleMaps .