Gomphrena medinae Zumaya-Mendoza S. & Sandoval-Ortega M.H., 2025

Zumaya-Mendoza, Silvia & Sandoval-Ortega, Manuel Higinio, 2025, An overlooked new species of Gomphrena (Amaranthaceae) endemic to Mexico, Phytotaxa 687 (1), pp. 9-14 : 10-13

Gomphrena medinae Zumaya-Mendoza S. & Sandoval-Ortega M.H. , sp. nov. ( Fig. 1 ).

Type:— MEXICO. Michoacán, Churumuco, Ejido Llano Ojo de Agua , 18°42’3.84”N 101°38’44.57”W, bosque tropical caducifolio, 431 m, 3 October 2013, Hernández & Sánchez 98 (holotype MEXU1409246 ; isotype MEXU1452787 ) .

Diagnosis:— Gomphrena medinae is similar to G. pringlei Coulter & Fisher (1892: 349) , but it can be distinguished by the oblanceolate-spathulate to lanceolate leaves arranged towards the base, 1.5–4.6 cm long (vs. oblong-lanceolate leaves, 1.0–2.0 cm long), inflorescences reddish to magenta, supported by a long peduncle and subtended by involucral leaves shorter than the inflorescence, 0.2–0.3 cm long (vs. involucral leaves equal to slightly longer than the inflorescence, 0.9–1.0 cm long), bracts close to ½ the size of the bractlets (vs. bracts almost the same size of the bractlets), bractlets crest width 0.5–0.6 mm (vs. 1.5–2.0 mm).

Description:—Herbs annual, up to 30 cm tall; stems erect, ascending, 8–30 cm long, pilose, trichomes 1.5 mm long, appressed, uniseriate, multicellular, with 3 to 6 cells, the last one towards the apex is the longest, armed. Leaves opposite, arranged towards the base, petioles inconspicuous, blades oblanceolate-spatulate to lanceolate, 1.5–4.6 × 0.2–0.6 cm, base long decurrent, margin entire, apex mucronate, adaxial surface pilose to glabrescent, abaxial surface densely hairy, with long appressed trichomes similar to those of the stem. Inflorescences globose, terminal, solitary, 1.0–1.5 × 0.5–1 cm, supported by 2 involucral leaves shorter than the inflorescence, 2–3 × 1.0– 1.5 mm, light green on the adaxial surface and pale green on the abaxial surface, ovate-lanceolate, sessile, base long excurrent, upper and lower surface pilose with long trichomes, peduncles 3–17 cm long. Flowers hermaphrodite, bract 1 broadly ovate, membranous, hyaline and glabrous, reaching more or less half the length of the bractlets, 3 × 1.3–1.8 mm, middle vein evident, long excurrent towards the apex; bractlets 2, crested, cymbiform, lanceolate, membranous, glabrous, reddish to magenta, longer than the tepals, 5.5–6.3 × 2.2–2.6 mm wide, the crest prolonged from the apex to above the middle, 0.5–0.6 mm wide, toothed; tepals 5, unequal, oblong-linear, 3 × 0.2–0.3 mm, scarious to membranous towards margin and apex, margin entire, 1-veined; trichomes white, undulated and simple, arranged from the base and decreasing in size towards the apex, up to 6 mm long; androecium with filaments fused into a staminal tube 3.2–4.0 mm long, lobes 5, 1.0 mm long, apex bifid alternating with a cleft, anthers 1.0– 1.3 mm long; gynoecium with subglobose ovary, 1.0– 1.5 mm diameter; style 0.6–1.8 mm long; stigma formed by two filiform branches 0.2–0.7 mm long. Fruit a utricle 1.6–2.4 × 1.0– 1.8 mm. Seed oblong, brown, 1.0– 1.2 mm diameter.

Etymology:—The new species is named after Rosalinda Medina Lemos, Mexican botanist, academic technician of the Instituto de Biología de la Universidad Nacional Autónoma de México and editor of “Flora del Valle de Tehuacán-Cuicatlán” who has made great contributions to the study of the Mexican flora (see e.g. Medina-Lemos 2008, 2009, 2013, 2022, Medina-Lemos & Fonseca 2009).

Distribution and habitat:— Gomphrena medinae grows in subtropical deciduous forest and secondary vegetation (derived from subtropical deciduous forest) in the Balsas Basin biogeographic province, states of Guerrero and Michoacán ( Fig. 2 ), between 125 to 500 meters a.s.l.

Phenology:—Flowering and fructifying from July to December.

Conservation status:— Gomphrena medinae is known only from five localities between the states of Guerrero and Michoacán, in the Balsas River basin. However, it is possible that this species has a wider distribution, since it occurs in secondary vegetation and even close to urban areas. Anyway, more extensive studies on the species are required to determine its conservation status. Therefore, following the guidelines of the IUCN criteria ( IUCN 2025), G. medinae is assessed as Data Deficient (DD).

Notes:— Specimens of Gomphrena medinae have been identified as G. pringlei for a long time. However, after consulting the protologue G. pringle ( Coulter & Fisher 1892) and the two isolectotypes of G. pringlei deposited in MEXU (barcodes MEXU00012331 and MEXU00012330; see Sandoval-Ortega & Zumaya-Mendoza 2023b). We confirm that the material here referred does not correspond to any previously described species. G. medinae can be differentiated from G. pringlei by several morphological differences (see diagnosis above, as well as Table 1 and Fig. 3 ).

Additional examined material (paratypes):— MEXICO. Guerrero: Ajuchitlán del Progreso, Cerro La Parotita de la localidad San Antonio de los libres, 18°9’46.9”N 100°34’11.5”W, 10 July 2014, Chamu 186 ( MEXU1439696 ) ; Zirándaro, Placeres del Oro , 8.44 km al N, 18°16’35”N 100°57’57”W, 26August 1999, Calónico, Mayorga & Armando 15697 ( MEXU1004848 ) . Michoacán: Arteaga, Carretera Nueva Italia-Playa Azul , en la desviación al infiernillo, 18°33’10.5”N 101°58’07.9”W, 17 September 1979, Soto & Silva 1625 ( MEXU303774 ) ; La Huacana, 7 km al W de La Huacana, sobre la carretera a Cuatro Caminos , 18°56’06.1”N 101°51’44.3”W, 18 October 1975, Rzedowski 33683 ( MEXU396272 ) .

Gomphrena pringlei examined material:— MEXICO. Estado de México: State of Mexico , 26 August 1890, Pringle 3152 ( MEXU) ; Huehuetoca, Extremo NE del Cerro Sincoque , 14 August 1986, Rzedowski 40330 ( MEXU) . Guerrero: Coahuayutla de Guerrero , La Corva, 5.46 km al N, 20 October 1999, Cálonico 17664 ( FCME) ; Huitzuco de Figueroa , 5 km al W de Tepecoacuilco de Trujano, 2 October 1981, Perea s.n. ( FCME) . Morelos: Amacuzac, Al Noreste de Amacuzac, 27 August 1986, De La Cruz 1255 ( MEXU) . Puebla: Cholula, La Ventana camino lado Poniente de Santiago Xalitzintla , 22 September 1987, Tlapa & Ubierna 539 ( MEXU) ; Cholula, Villa turistica Buenavista , por el lado Noroeste de Santiago Xalitzintla , 8 September 1987, Tlapa & Ubierna 369 ( MEXU) ; Cholula, Camino a Paso de Cortes , por el lado Poniente de Santiago Xalitzintla , 15 September 1987, Tlapa & Ubierna 482 ( MEXU) ; Parque Estatal Gral. Lázaro Cárdenas , 16 August 1994, Martínez Romero 403 ( MEXU) ; San José Chiapa, Cerro Aproximadamente a 1 km al E del Carmen , por la carretera Acajete-Oriental , 10 November 2006, Contreras 8518 ( FCME) . Tlaxcala: Domingo Arenas, San José Techopa , 26 September 1988, Santacruz 428 ( MEXU) .

Figures

FIGURE 1. Gomphrena medinae. a. Habit, b. Inflorescence with involucral leaves, c. Flower with bract and bractlets, d. Tepal, e. Staminal tube, f. Interior view of the staminal tube with gynoecium and stigma. Drawn from the type specimens by Ollitzin Fortis.

FIGURE 2. Distribution of Gomphrena medinae and G. pringlei. States: CDMX= Ciudad de México, EDOMEX= Estado de México, GRO= Guerrero, HGO= Hidalgo, MICH= Michoacán, MOR= Morelos, OAX= Oaxaca, PUE= Puebla, TLAX= Tlaxcala.

FIGURE 3. Detail of different structures of the inflorescence of Gomphrena medinae and G. pringlei.A) involucral leaves in inflorescence of G. mediane. B) involucral leaf of G. pringlei. C1) bract of G. medinae. D1) bractlet of G. medinae E1) bractlets enclosing the flower of G. medinae. C2) bract of G. pringlei. D2) bractlet of G. pringlei. E2) bractlets enclosing the flower of G. pringlei.