Aristolochia crocea Paizanni, 2023

Guillén, Anna Paizanni, Bautista, Elihú & Douterlungne, David, 2023, Aristolochia crocea, a new species of Aristolochia subsection Pentandrae (Aristolochiaceae) from Guerrero, Mexico, Phytotaxa 616 (2), pp. 128-138 : 129-137

Aristolochia crocea Paizanni , sp. nov. ( Figures 1–3 )

Type:— MEXICO. Guerrero: Municipality Atlixtac, 5 km west of Atlixtac, on the way to Petatlán , 1550 m, 29 October 2022, L. J. González Almazán & C. Gallardo 238 (holotype: IEB!, isotypes: MEXU!, UAGC!) .

Aristolochia crocea stands out for its flowers, which have a pale-yellow throat and a greenish-yellow limb when young, which later turns to saffron (yellow-orange). Its leaf blades are trilobate, with a narrowly triangular to triangular middle lobe and rounded lateral lobes. Its flowers resemble Aristolochia oaxacana Eastwood (1909: 603) , as both have shades of yellow on the limb, but the latter differs from the new species by its purplish-red borders, purplish-red throat, and lanceolate-ovate to ovate leaf blades. Other species with trilobate leaves are A. nelsonii Eastwood (1909:604) , which differs from A. crocea in its oblanceolate-ovate shaped middle lobe and obtuse rounded or acute lateral lobes; A. variifolia Duchartre (1854:65–66) , with a rounded or acute middle lobe and obtuse or rounded lateral lobes; and A. versabilifolia Pfeifer (1970:78–82) , with a narrowly elliptic to widely triangular middle lobe and rounded lateral lobes.

Geophytic herb, procumbent and climbing, root 5.0–10.0 × 0.4 –1.4 cm; underground stems with swollen nodes, (2.5–)6.5–13.0 × 0.2–0.4(–0.8) cm; internodes straight (rarely slightly geniculate) (0.9–)1.0–2.0(–4.5) × 0.1– 0.15(–0.2) cm, greenish yellow to green purplish, pilose. Petioles terete, (0.3–)0.8–1.5(–2.2) × (0.03–)0.05–0.1(–0.15) cm, greenish yellow to green purplish, villose. Leaf blades variable along the branch, deltate to triangular near the root and trilobate with a narrowly triangular to narrowly elliptic middle lobe and rounded lateral lobes toward the tip of the branch; apex acute to attenuate, base auriculate, (1.4–)3.0–5.0(–6.7) × (0.8–)1.3–2.5(–4.5) cm, palmately veined, actinodromous, margin entire; adaxial leaf side pale olive, veins pale olive to brownish, strigose; abaxial leaf side pale green to pale yellow, veins pale yellow and purplish red at the base of the leaf, pilose, villose along the veins. Flowers axillary, solitary, peduncle bracteolate, (0.2–)0.3–0.7(–1.5) × 0.05–0.08 cm, villose. Bracts lanceolate to triangular, base semi-amplexicaul, 0.25–0.3(–0.5) × 0.1–0.25 cm, pilose. Ovary inferior, fusiform to obclavate, (0.2–)0.3–0.5 × 0.1–0.2(–0.3) cm, villose. Perianth geniculate or straight, 1.4–2.5 cm long, pale yellow to greenish yellow becoming orange toward the limb, pilose; limb lanceolate-ovate to ovate, apex acute to attenuate with a tuft of hairs at the tip, base cordate, (0.5–)0.7–1 × (0.3–) 0.4–0.5 cm, greenish yellow when young, turning saffron (yellow orange) with age, surface glabrous, in lateral view flat; throat obovoid to ellipsoid, 0.2–0.3 × 0.2–0.4 cm, pale yellow with translucent conical uniseriate trichomes; tube straight when young, bent (80º–)90º–120º with age, widened toward the limb, basally straight, (0.4–)0.7–1.2 × 0.25–0.4 cm, internal part pale yellow to yellow greenish, with conical uniseriate, translucent trichomes; utricle gibbous, ellipsoid to obovoid, (0.3–)0.4–0.6 × 0.3–0.4(–0.5) cm, internal part purplish red, base pale yellow with multicellular mucilaginous trichomes; syrinx eccentric, tubular to infundibuliform, 0.15 cm long, 0.12 cm wide at the apex and 0.25–0.4 cm wide at the base (when infundibuliform). Gynostemium coroniform, stipitate 0.3 cm long; stipe 0.07–0.15 cm long, with 5 stigmatic lobes, 0.1 cm long, and 5 anthers, 0.08–0.1 cm long. Fruit a capsule, asymmetrical spheroidal to ellipsoid, (0.8–)1–1.4 × 0.7–1.0(–1.2) cm, greenish yellow with purplish red veins when young, dark brown with age, villose, with septicidal dehiscence at the apex. Seeds deltoid with angular edges, 0.4–0.5 × 0.3–0.4 cm, upper part black with granular surface, lower part slightly concave, yellowish brown with a raphe ( Figures 1 , 2 , Table 1).

TABLE 1. (Continued)

Phenology: —This species has been found flowering in June and bearing fruits in November.

Distribution and habitat: — Aristolochia crocea is only known from its type locality in the municipality of Atlixtac, Guerrero ( Figure 3 ). It grows in pine-oak forests at an elevation between 1500 and 1550 m, where it coexists with Pinus aff. patula Schlechtendal & Chamisso (1831: 354) , Brahea dulcis (Kunth) Martius (1838: 244, t.137), Quercus peduncularis Née (1801: 270) , Q. elliptica Née (1801: 278) , Q. liebmannii Oersted ex Trelease (1924: 66 pl.75), and Ipomoea sp. Linnaeus (1753: 159), among others.

Preliminary conservation assessment: —Since Aristolochia crocea is only known from its type locality, this species should be considered as Critical Endangered (CR) based on its Extent of Occurrence (0.000 km 2) and the Area of Occupancy (4,000 km 2), as calculated by GeoCAT—http://geocat.kew.org. This situation—a species only known from its type locality—occurs in several Aristolochia species .

Etymology: —The species epithet is derived from the Latin word croceus, which means saffron-colored (yellow-orange), referring to the color of the limb.

Additional specimens of Aristolochia crocea examined:— MEXICO. Guerrero: Mun. Atlixtac, 5 km to the east of Atlixtac, on the way to Petatlán , 1500 m, 21 June 2014, R. Cruz & E. Hernández 9174 ( HUAP!) .

Specimens of Aristolochia nelsonii examined: — MEXICO. Chiapas: Mun. Tuxtla Gutiérrez , mirador Iris, al O de Tuxtla Gutiérrez , carr. 190 Tehuantepec-Tuxtla Gutiérrez , 700 m, 25 June 1991, L. M. González V. et al. 3829 (IEB). Oaxaca: San Geronimo , 200 ft., 1–5 July 1895, E. W. Nelson 2769 (holotype GH!, JSTOR image); Mun. San José Tenango, 10.3 km antes de entrar a Tenango , aprox. a 29 km de la carr. principal, 29 July 1996, E. Mendoza L. & C. E. Glass 162 ( IEB); Mun. San Bartolo Yautepec, donde se junta arroyo Calabara y camino de la Cruz, 863 m, 13 August 2011, D. López P. 1069 ( IEB); Mun. San Pedro Huamelula, terreno del Sr. Leonel Ciriaco Gómez , 219 m, 19 June 2009, J. Leyva M. 183 (IEB) ; Mun. Santa María Huatulco, 2 km al N de la Bahía de Cacaluta , a orillas de una laguna pequeña, 25 m, 16 July 2003, M. Elorsa C. 6982 ( IEB); Mun. Santiago Astata , Puente Zimatán, 4 km al N camino a Xadani , 24 August 1999, E. Martínez S. et al. 32457 ( IEB); Barra de la Cruz , 1 km al W por la vereda que comunica con Zimatán , 70 m, 7 August 2000, M. Elorsa C. 3362 ( IEB); Arroyo Grande , 2 km al W de Barra de la Cruz, 140 m, 18 June 2000, M. Elorsa C. 3127 ( IEB); Camino viejo que comunica a la playa de Barra de la Cruz , 15 m, 14 July 2000, M. Elorsa C. 3264 ( IEB); La Playita, 390 m (lr) al SW del Peñasco de Barra de la Cruz , 50 m, 4 August 2001, A. Saynes V. et al. 2430 (IEB) ; 2 km al N del puente Zimatán, sobre la brecha a Xadani , 100 m, 9 September 2002, M. Elorsa C. 6204 ( IEB); Vereda El Aguaje , arriba del arroyo, 70 m, 1 September 2009, E. J. Lott et al. 5913 ( IEB) .

Specimens of Aristolochia oaxacana examined: — Mexico. Oaxaca: Clajiaco, H . Galeotti 214 (holotype GH!, Jstor image); Mun. San Pedro y San Pablo Teposcolula , 5 km al S de Teposcolula, Yodonocuito, 2180 m, 11 July 1982, A . García M . 953 ( IEB); Mun. San Juan Mixtepec, Peña Blanca , 12 km al W de San Juan Mixtepec, 2100 m, 10 July 1988, J . Reyes S . 378 A (IEB); Mun. Villa Tejúpam de la Unión, aprox. 1 km antes de llegar a Tejúpam de Tamazulapan , subiendo por un camino hacia el cerro, 2092 m, 21 August 2014, A . Paizanni-Guillén et al. 249 ( IEB) .

Specimens of Aristolochia variifolia examined: — Mexico. Chiapas: Mun. Villaflores, en el predio Monterrey, ca. Del arroyo “Salto Chiquito”, 770, 5 August 2002, A. Reyes-García 5232 ( MEXU). Guerrero: Mun. Chilpancingo , 3.5 km al SE de Soyatepec por el camino al cerro El Toro, 1000 m, 14 November 1987, L. C. Rodríguez M. 262 L ( IEB); Mun. Juan R. Escudero, Tierra Colorada , 3 March 1968, H. Kruse 1657 ( IEB, MEXU); Tierra Colorada, 11 April1968, H. Kruse 1673 ( IEB); Mun. Tecpan de Galeana, Roca de Tlalcoyunque , 17 September 2012, A. Bourg et al. 24 ( IEB). Oaxaca: Cordillera secus mare Pacificum , 1840, H. Galeotti 208 (isotype P!, JSTOR image) .

Specimens of Aristolochia versabilifolia examined: — Mexico. Guanajuato: Mun. Allende, alrededores de Rancho Viejo, 1900 m, 25 September 1994, J. Rzedowski R. 52663 ( IEB); Mun. Comonfort , 5 km al ENE de Empalme Escobedo, 1900 m, 28 July 1986, J. Rzedowski R. 40109 ( IEB); Mun. Dolores Hidalgo, 27 km al S de Dolores Hidalgo, sobre la carr. a San Miguel de Allende , 1900 m, 18 October 1986, J. Rzedowski R. & G. C. de Rzedowski 41065 ( IEB); Mun. San Miguel de Allende, 17 km al NNW de San Miguel de Allende, sobre la carr. a Dolores Hidalgo, 1900 m, 23 August 1988, J. Rzedowski R. 47135 (IEB) ; Predio El Cortijo, 16 km al NE de la Cd. de Dolores Hidalgo, sobre la carr. a San Luis de la Paz , 1906 m, 12 October 1996, R. V. Ocampo V. 152 ( IEB); Mun. Santa Cruz de Juventino Rosas, 3 km al S de Pozos, sobre la carr. a San José Iturbide , 2200 m, 10 August 1991, J. Rzedowski R. 50813 ( IEB); Mun. Ocampo, Santa Barbara, siguiendo por la calle Juárez hasta las afueras del pueblo y el final del camino, 2251 m, 12 September 2014, A. Paizanni-Guillén et al. 271 ( IEB); Mun. San Felipe , 4 km al NE de El Zapote, alrededores de La Ventanilla, 1900 m, 20 July 1991, J. Rzedowski R. & G. C. de Rzedowski 50638 ( IEB); Mun. San Luis de la Paz, Rancho La Misión , 8 km al N de San Luis de la Paz, 2900 m, 11 October 1988, E. Ventura V. & E. López 6121 ( IEB); La Labor, 2000 m, 25 September 1990, E. Ventura V. & E. López 8831 ( IEB); La Merced, carr. a Pozos San José Iturbide , 2100 m, 31 July 1991, E. Ventura V. & E. López 9357 ( IEB); Carr. San Luis de la Paz-Xichú, 4 km al E de Palmarito de la Misión Chichimeca , 2075 m, 27 August 2014, A. Paizanni-Guillén et al. 253 ( IEB); Carr. San José Iturbide-Mineral de Pozos, 3 km aprox. de Mineral de Pozos , 2201 m, 26 August 2014, A. Paizanni-Guillén et al. 252 ( IEB); Mun. Victoria, cerro de la Luz, camino a Xichú , 1800 m, 26 July 1991, E. Ventura V. & E. López 9338 ( IEB). Hidalgo: Mun. Cardonal , ca. de El Cubo, 2000 m, 6 May 1990, J. Rzedowski R. 49324 ( IEB). Jalisco: Mun. Ojuelos, nopalera silvestre predio ¨ Las Cacalotas ¨ rumbo a la carretera Ojuelos-Aguascalientes , 2060m, 2 May 2005, Luz A. García-R. 1116 ( IBUG). Querétaro: Mun. Cadereyta de Montes, 3 km al S de Vizarrón , 2150 m, 1 August 1990, J. Rzedowski R. 49684 ( IEB); 1 km al NE de Higuerillas , 1400 m, 17 October 2001, S. Zamudio R. 11812 ( IEB); Mun. Colón, alrededores de la ExHacienda, Santa María del Mexicano , 1900 m, 10 October 1994, E. Pérez C. & E. Carranza G. 2766 ( IEB); Mun. Corregidora , Cañada de la Plata, 1900 m, 22 October 2013, L. Hernández S. 6638 ( IEB); Mun. Tequisquiapan, alrededores de Tequisquiapan , 2100 m, 12 June 1992, R. Hernández M. et al. 9942 ( IEB). San Luis Potosí , 1878, C. C. Parry &. Ed. Palmer 766 (isotype BM!, JSTOR image); Mun. Guadalcázar , aprox. 1.5 km después de el poblado de El Oro, viniendo de Guadalcázar, 1619 m, 4 September 2019, A. Paizanni-Guillén & J. M. Ramírez-Amezcua 477 ( IEB); Mun. Río Verde, Pasando el poblado “La Loma” por el camino que se dirige al cerro rocoso, 1167 m, 28 August 2014, A. Paizanni-Guillén et al.254 ( IEB); cerro El Agujón, ± 1 km al SW de La Alameda , 1700 m, 7 August 2007, S. Zamudio R. et al. 13825 ( IEB). Zacatecas: Mun. Nochistlán de Mejía, potrero de Don José Carrillo , salida Río de Santa Gertrudis , Sierra del Laurel , 2160 m, 29 April 2006, J. Martínez R. 604 ( IEB); Mun. Villanueva, ca. de la carr. 54 entre los poblados Malpaso y La Soledad, 2110 m, 6 October 2019, A. Paizanni-Guillén & J. M. Ramírez-Amezcua 485 ( IEB) .

Comments:—The most similar species to Aristolochia crocea is A. versabilifolia from the locality of Rio Verde ( Figure 4E , Table 1), San Luis Potosí, Mexico, due to the similarities of its trilobate leaves with a long and narrow middle lobe, but this lobe is oblong to ligulate, with obtuse to acute apex and lateral lobes usually obtuse, rarely rounded. In contrast, A. crocea has a narrowly triangular to triangular middle lobe and rounded lateral lobes ( Figures 1A , 2E , Table 1). This is the main morphological character separating the two species and should therefore be recognized under field conditions, as dried specimens often have longitudinally pressed flowers, which makes the shape of the front limb difficult to see.

Hereafter, a dichotomous key is presented, based upon critical morphological features to distinguish A. crocea from similar Pentandrae species, such as the frontal part of the limb (shape, color, surface, and size), perianth size and, leaf size and form.

Key to distinguish Aristolochia crocea and its morphologically closest relatives

1 Limb widely ovate, apex acuminate to cuspidate............................................................................................. Aristolochia variifolia

- Limb lanceolate-ovate to ovate, apex acute, attenuate, long caudate, obtuse or retuse .....................................................................2

2 Perianth 4.2–6.0(–10.2) cm long; limb apex long caudate................................................................................................. A. nelsonii

- Perianth no more than 4.0 cm long; limb apex acute to attenuate or obtuse to retuse .......................................................................3

3 Leaf blades trilobate, triangular to deltate or hastate; petioles 0.8–2.5 cm long; throat pale yellow or yellow with purplish-red spots ...................................................................................................................................................................................................4

- Leaf blades lanceolate-ovate or ovate; petioles (0.2–)0.3–0.5(–0.7) cm long; throat purplish-red ................................. A. oaxacana

4 Leaf blades when trilobate with the middle lobe narrowly elliptic to widely triangular; limb color purplish-red to maroon, surface with papillose protuberances; throat yellow with purplish-red spots......................................................................... A. versabilifolia

- Leaf blades when trilobate with the middle lobe narrowly triangular to narrowly elliptic; limb color greenish-yellow when young, becoming saffron (yellow-orange) with age, surface smooth; throat pale yellow ............................................................... A. crocea

Figures

FIGURE 1. Aristolochia crocea. A. Branch. B. Perianth, inferior ovary, bract, and peduncle. C. Front view of the limb. D. Interior view of the utricle, which is composed of the gynostemium and the syrinx. E. Fruit. Based on L. J. González Almazán & C. Gallardo 238. Drawing by José Manuel Ramírez Amezcua.

FIGURE 2. General morphology of Aristolochia crocea. A. Front view of the limb. B. Flowers. C. Lateral view of the perianth. D. Fruit. E. Habit. Photographs by Luis Javier González Almazán.

FIGURE 3. Distribution of Aristolochia crocea and morphologically closest species based on herbarium specimens.

FIGURE 4. Morphologically closest species to Aristolochia crocea. A–B. Aristolochia oaxacana (A. Paizanni-Guillén et al. 249 (IEB)). C. Aristolochia nelsonii. D. Aristolochia variifolia. E–F. Aristolochia versabilifolia (E. A. Paizanni-Guillén & J. M. Ramírez-Amezcua 485 (IEB) and F. A. Paizanni-Guillén et al. 254 (IEB)) Photographs by A. Paizanni Guillén. (A–B, E–F), Samuel Velásquez (C) and Saúl Borja (D).

Tables

TABLE 1. Morphological characteristics of Aristolochia crocea and their closest species.

Character	A. crocea	A. nelsonii	A. oaxacana	A. variifolia	A. versabilifolia
color	pale yellow	white	purplish red	bright yellow to greenish	yellow with purplish red spots
Tube: bent	straight when young, bent (80º–) 90º–110º(–120º) with age.	(20º–)40º–110º(–140º)	straight or bent 140º–150º	20º–40º (–75º)	usually straight or bent 120º–130º
size	(0.4–)0.7–1.2 × 0.25–0.4	(0.1–)0.8–1.7 × 0.2–0.4(–0.6)	0.7–1.2(–1.8) × 0.2–0.3	(0.7–)1.0–2.0 × 0.3–0.6	(0.4–)0.6–1.5 × 0.2–0.5
Utricle: size	(0.3–)0.4–0.6 × 0.3–0.4(–0.5)	0.6–0.8 × (0.3–)0.4–0.6	0.5–0.7(–0.8) × (0.2–)0.3–0.4	(0.5–)0.7–1.7 × (0.2–)0.4–0.6	(0.2–)0.4–0.8 × (0.3–)0.4–0.7
Fruit: shape	asymmetrical spheroidal to ellipsoid	oblate to spheroid	subglobose to ellipsoid, asymmetric	ellipsoid	ellipsoid, subglobose or ovoid to pyriform
size	(0.8–)1–1.4 × 0.7–1.0(–1.2)	1.3–2.0 × 1.0–1.6	(1.2–)1.5–2 × 1.0–1.7	1.5–2.6 × 1.0–1.8	(0.7–)1.0–1.5 × (0.6–)1.0–1.5
Distribution (Mexican states)	Guerrero (Figure 3)	Chiapas and Oaxaca (Figure 3)	Oaxaca (Figure 3)	Chiapas, Guerrero and Oaxaca (Figure 3)	Guanajuato, Hidalgo, Jalisco, Querétaro, San Luis Potosí and Zacatecas (Figure 3)
Elevation	1500–1550 m	15–1500 m	2000–2170 m	195–1000 m	1167–2000 m
Vegetation	pine-oak forest	tropical deciduous forest	pine-oak forest in secondary vegetation, ruderal vegetation	tropical deciduous forest and oak forest	xerophyllous scrub