Grusonia pulvinata D.Donati, 2025

Donati, Davide, 2025, Grusonia pulvinata, a new sibling species within G. vilis s. l. (Opuntioideae: Cactaceae), Phytotaxa 712 (2), pp. 87-106 : 98-103

Grusonia pulvinata D.Donati sp. nov.

Holotype: — MEXICO, San Luis Potosí, Mpo. Guadalcazar, San Juan Sin Agua , 1365 m a.s.l., sand-clayish alluvial plains with accumulation of evaporitic deposits; 2014 november 07, Hinton et Donati 29502 ( GBH!) ( Fig. 7 ).

Diagnosis:— Grusonia pulvinata is similar to G. vilis , but it differs in: plant body densely branched, pulvinate; thin taproot; branches mainly deflexed, as ascending sequence of axes comprised of distinct joints; obovate joints strongly attached to the previous joint (or stem); shorter central spines, up to 31 mm long; ovary with sparse areoles, bristle spines rare or absent and few glochids; proliferation of sterile fruits. Diploid.

Description:—Plant succulent, cespitose pulvinate, forming compact cushions of mainly deflexed branches, up to 60 cm wide and 26 cm tall. Thin taproot. Joints obovate to elliptic, often curved, 36–58 mm long and 21–36 mm wide, firmly attached to the previous joint; tubercles 6–12 mm long and 2–4 mm wide, mainly inflated. Areoles 3–5 mm wide; areole protrusions on the areoles close to the base of the plant body. Leaves succulent, conical-elongated, up to 8 mm long, early deciduous. Central spines (1–)4(–8), up to 31 mm long, the lower downward–pointing, the upper erect–spreading, acicular, retroversely barbed, bulbous at the base, terete, surface ridged, brown-reddish (red during growth), the lower sometimes grayish, covered for the apical third by a white, vestigial tunica. Radial spines 6(–8), 7–14 mm long, acicular, white. Glochids not dense, 2–4 mm long, yellowish, produced from the adaxial portion of the areole, mainly erect–spreading; glochids dense on areole protrusions, spreading in all directions. Flower sessile, hermaphroditic, 25–46 mm diameter at the anthesis; outer tepals 6–11 mm long and 3–5 mm wide, subulate to apiculate, pink-purplish; inner tepals 12–21 mm long and 5–8 mm wide, spatulate-cuneate, apiculate to mucronate, magenta coloured with green base; filaments green, apically pinkinsh, thigmotactic; style greenish; stigma 5–9 lobed, greenish; pericarpel obconical and short, 20–45 mm long, with sparse areoles containing few or absent short bristle spines, short spines and, adaxially, few short glochids. Fruit green-reddish, 21–48 mm long; fruit areole protrusions very small or absent, containing short glochids; sterile fruits sometimes proliferating, generally producing new flowers. Seeds suborbicular, 3–5 mm wide, tan-yellowish ( Fig. 8 )

Etymology:—The epithet pulvinata means pulvinate, cushion shaped.

Karyology:— Grusonia pulvinata is a diploid, with 2n = 22 chromosomes. ( Figure 8 )

Phenology:—Flowering from April to June. Setting fruits usually from September.

Habitat:— Grusonia pulvinata grows mainly on sandy-clayish alluvial plains with an accumulation of evaporitic deposit, often associated with gypsicolous and halophilous species.

Distribution:— Grusonia pulvinata is distributed from the El Huizache area to north-west of Matehuala, San Luis Potosí, and adjacent, restricted areas in Zacatecas, Mexico.

Conservation status:—As a result of the survey, the distribution of Grusonia pulvinata appears to be restricted to plains with evaporitic deposits of north-western San Luis Potosí and adjacent areas in Zacatecas (about 8000 km ²). Thousands of plants grow north-west of Matehuala (Donati, pers. observ.), but the number of individuals of the total population is difficult to assess, since G. pulvinata very often grows in hard-to-locate clearings in the tall shrubby vegetation (Yucca-Prosopis) of San Luis Potosí. Thus, following IUCN Red List Categories and Criteria (2001, 2012), it should be considered as Data Deficient (DD).

Taxonomic key:—A proposed diagnostic key follows:

1. Body cespitose pulvinate, branches mainly deflexed, joints firmly attached and very difficult to disarticulate without any damage ............................................................................................................................................................................................................2

1. Body cespitose sparsely branched, branches linear, joints weakly attached and easy to disarticulate...............................................3

2. Thick/tuberous taproot, transversely obtriangular central spines, flower yellow, red/greenish filaments, long sterile fruits not proliferating ............................................................................................................................................................. Grusonia aggeria

2. Thin taproot, short and reddish acicular central spines, flower red/magenta, green filaments, short reddish sterile fruits sometimes proliferating .......................................................................................................................................................... Grusonia pulvinata

3a. Flower yellow............................................................................................................................. Grusonia grahamii subsp. grahamii

3b. Flower red/magenta............................................................................................................................ Grusonia grahamii subsp. vilis

Specimens examined:— Grusonia pulvinata . MEXICO, San Luis Potosí: Cedral, E of Vanegas, 1740 m a.s.l., 2014, Hinton et al. 29503 (GBH29503); Cedral, N of Vanegas, 1716 m a.s.l., 2014, Hinton et al. 29501 (GBH 29501); Catorce, 6 km W of Estación Catorce, Tanque de Dolores, 1999, Goettsch and Gómez 168 (MEXU900960, pro Grusonia vilis ); Guadalcazar, near Entronque Huizache, 1 km to San Juan sin Agua, 1978, 1300 m a.s.l., Leuenberger, Schiers and Ahuatzin 2631 (MEXU495033, pro Grusonia vilis ); Vanegas, close to “Venegas”, 1959, Bravo H. 3528 (MEXU60757, pro Grusonia (Opuntia) vilis ); Guadalcázar, 8 km NW of Entronque Huizache on the road to Matehuala, 1996, 1240 m a.s.l., Gómez H. And Bárcenas 939 (MEXU741438, pro Grusonia vilis ); Guadalcázar, 3 km W of El Milagro, 1995, 1230 m a.s.l., Gómez H. and Bárcenas 688 (MEXU741494, pro Grusonia vilis ); Villa de Guadalupe, 2 km on the road to San Juan sin Agua from the road San Luis Potosí-Matehuala, 1996, 1225 m a.s.l., Gómez H. and Bárcenas 755 (MEXU761873, pro Grusonia vilis ); Guadalcázar, 1 km NE of El Milagro, 1995, 1210 m a.s.l., Gómez H. and Cattabriga 444 (MEXU761882, pro Grusonia vilis ); Guadalcázar, plains 2–3 km E of Highway 57 (San Luis Potosí-Matehuala), about 6 km N of Entronque Huizache, 1996, 1280 m a.s.l., Hernández, Gómez H. and Bárcenas 2701 (MEXU763734, pro Grusonia vilis ); Guadalcazar, 10 km E of Norias del Conde or Norias del Refugio, 1996, 1305 m a.s.l., Gómez H. and Santos Martínez s.n. (MEXU771808, pro Grusonia vilis ); Villa de Guadalupe, 2 km W of Santa Teresa, 8 km al W of Highway 57, between Entronque Huizache and Matehuala, 2005, 1452 m a.s.l., Gómez H., Goettch and Brailovsky 2367 (MEXU1284001, pro Grusonia vilis ); Guadalcázar, 1 km NE of El Milagro, 8 km E of the road Matehuala-Entronque Huizache, 1995, 1195 m a.s.l., Gómez H. and Bárcenas 664 (MEXU736565, pro Grusonia vilis ).

Grusonia grahamii subsp. vilis . Mexico, Zacatecas: Zacatecas, 1907, Lloyd #14 (US00117071; holotype) ;

Zacatecas, 1907, Lloyd #14 ( NY00688044 ; isotype) ; Mazapil, Cedros , 1999, 1850 m a.s.l., Puente 1619 ( ASU0054219 ) ;

Mazapil, SW of Cedros, 1998, 1750 m a.s.l., Baker 12831 (DES0050823); SE of Concepcion del Oro, Loma el Peyote, 1998, 1900 m a.s.l., Baker 12834 (DES0050822); Mazapil, NW of Lomas de Renuevas, slopes of Carpintero; Mazapil, 24.2 km from Cedros on the road to Matamoros, 500 m N on dirty road, 2005, 1551 m a.s.l., Brailovsky, Hernánez, Gómez and Navarro 50 (MEXU1203398, pro Grusonia sp. ); Melchor Ocampo, hills 19 km W of M. Ocampo to El Trebol, 2005, 2071 m a.s.l., Brailovsky and Navarro 380 (MEXU1203734, pro Grusonia moelleri ); Mazapil, plains E of Matamoros, 2005, 1654 m a.s.l., Brailovsky and Navarro 428 (MEXU1203737, pro Grusonia moelleri ); Mazapil, hills NW of Sierra "El Mascarón": dirty road N of Cedros, after km 4 turn SE on a track to the sierra, 2005, 1879 m a.s.l., Brailovsky, Gómez and Goettsch 105 (MEXU1203740, pro Grusonia moelleri ); Mazapil, plains close to Peñasco mine, 10 km E of Cedros to Mazapil, 2005, 1934 m a.s.l., Brailovsky and Ibarra 285 (MEXU1203741, pro Grusonia moelleri ); Melchor Ocampo, N of "El Trébol": dirty road from Matamoros to Melchor Ocampo, 2005, 1751 m a.s.l., Brailovsky 69 (MEXU1207215, pro Grusonia moelleri ); Mazapil, NW of Lomas de Renuevas, slopes of Carpintero: 24.2 km from Cedros on the road to Matamoros, 2005, 1571 m a.s.l., Brailovsky, Hernández, Gómez and Navarro 50 (MEXU1207222, pro Grusonia moelleri ); Mazapil, hills N of Cedros, 5 km N of Cedros to El Jaguey, 2005, 1750 m a.s.l., Brailosvsky and Navarro 411 (MEXU1207243, pro Grusonia moelleri ); Mazapil, 33 km from Cedros to Matamoros, road to el Vergel, 2005, 1937 m a.s.l., Brailovsky, Gómez and Goettsch 180 (MEXU1207253, pro Grusonia moelleri ); Mazapil, Los Llanos, 2005, 1817 m a.s.l., Brailovsky 264 (MEXU1207256, pro Grusonia moelleri ); Mazapil, Rancho de Renuevas: 19.4 km from Cedros to Matamoros, 2005, 1711 m a.s.l., Brailovsky, Hernández, Gómez and Navarro 31 (MEXU1207266, pro Grusonia moelleri ); Mazapil, 18 Km S of Tecolotes on the track to Candelaria, 2005, 1956 m a.s.l., Brailovsky 459 (MEXU1207279, pro Grusonia moelleri ); Mazapil, Tanque Nuevo, road to EL Vergel, 2005, 1850 m a.s.l., Brailovsky and Ibarra 237 (MEXU1210342, pro Grusonia moelleri ); Mazapil, Los Barriales del Vergel, 17.5 from Cedros to Matamoros, 2005, 1616 m a.s.l., Brailovsky, Hernández, Gómez and Navarro 9 (MEXU1210343, pro Grusonia moelleri ); Mazapil, S of El Vergel: 16 Km. W of Cedros to Tecolotes and Ahuichila, 2005, 1682 m a.s.l., Brailovsky 425 (MEXU1210344, pro Grusonia moelleri ); Mazapil, N of Sabana Grande, 21.5 km SE of Cedros, 2005, 1874 m a.s.l., Brailovsky, Gómez and Goettsch 141 (MEXU1210381, pro Grusonia moelleri ); Mazapil, 2 km N of Tecolotes, 2005, 1840 m a.s.l., Brailosvsky and Gómez 155 (MEXU1210382, pro Grusonia moelleri ); Mazapil, 4 km SE of Tecolotes, dirty road to Candelaria, 2005, 1771 m a.s.l., Brailosvsky and Navarro 494 (MEXU1210425, pro Grusonia moelleri ); km 212 carretera Zacatecas-Saltillo, 1965, 1820 m a.s.l., Bravo H. 1965-05 (MEXU61056, pro Grusonia (Opuntia) vilis ); Km 261 of the road Zacatecas-Saltillo, 1973, 1900 m a.s.l., Sánchez Mejorada 1780 (MEXU158973, pro Grusonia (Opuntia) vilis ). Mexico, Coahuila: E of Viesca, 2014, 1137 m a.s.l., Hinton et al. 29536 (GBH 29536). Mexico, Durango: Lerdo, South of Lerdo, 2014, 1220 m a.s.l., Hinton et al. 29492 (GBH 294929). Mexico, San Luis Potosí: Cedral, E of Vanegas, 2014, 1740 m a.s.l., Hinton et al. 29504 (GBH 29504); Cedral, El Salado, 2014, 1723 m, Hinton et al. 29507 (GBH 29507).

Grusonia aggeria . USA, Texas: Brewster County, Tornillo Creek Basin, N. of Hot Springs, Big Bend Natl. Park, 1952, Blakley B-1422 ( DES00001429 ) ; USA, Texas: Brewster County, Big Bend Ranch State Park, ca. 2.9 miles N of Lajitas gate, E of road, 1463 m a.s.l., 1995, Hodgson 9059 ( DES00041946 ). Mexico, Chihuahua: MEX 16, 16.8 mi N Aldama , 8 mi S El Morrion, 1978, Lehto k-8126 ( ASU0059103 ) ; Mexico, Chihuahua: 16 km NNW of Torreoncitos, NW of km 39 along Hwy 22 (49), NW of Jimenes, 500 m east of Arroyo Flórido at La Parra, 1997, Baker 12390 ( ASU0058909 ) ; Mexico, Chihuahua: 1 km east of Mercurio ; 25 km NE of Escalón ; 2 km NNW of the summit of Cerro Piloncillo, 2004, Baker 15667 ( ASU0058911 ) ; Mexico, Coahuila: Bolson de Mapimi, 13.3 miles E of El Cinco. , 1971, Keil k-8126 ( ASU0059100 ). Mexico, Coahuila: Ca. 10 km WSW of Cuatro Ciénegas ; Sierra La Madera , Loma Larga, 1998, Baker 12817 ( ASU0059096 ) .

Grusonia grahamii . USA, Texas: El Paso County, Hueco Mtns., limestone hills located 2.5 mi E of Nations East Well & 3 mi west of Hueco Tanks State Historical Park , 1991, Worthington 19354 (UCR-69037) ; USA, Texas: El Paso County, El Paso, Resler Arroyo near I-10, 2003, Worthington 32137 (UCR-161605) ; USA, Texas: El Paso County, El Paso, NW edge of El Paso, a mile or two of Mesa Road / Drive, a short distance N of Belvedere St. , ca 0.5 mile’ E. of intersection of Belvedere and Resle , 1990, Zimmerman 2631 ( DES00039361 ) ; USA, Arizona: Grown in cultivation at Desert Botanical Garden, Phoenix, originally received as a plant collected by Patrick Quirk s. n., 14 November 1997 from Texas, Terrell County, Gatlin Ranch, Ward s.n. ( DES00063754 ) ; USA, Texas: Brewster County, Big Bend National Park, just N of Willow Springs Site, 1995, Hodgson 8982 ( DES00041829 ). Mexico, Chihuahua: Mpio. de Ciudad Juárez. Sierra Juárez. , 1984, Worthington 11680 ( ASU0059101 ) ; Santa Cruz Microondas Station, Rte 45 ca. 54 mi S of Chihuahua City, 1976, Pinkava P-13374 ( ASU0059098 ) ; 5 km NW of La Cruz and Rio Conchas, just north of Arroyo La Colorada, 2004, Baker 15662 ( ASU0054186 ). Mexico, Coahuila: North of Ocampo, 1 km NE of Guadalupe, east of Sierra del Mula , 2004, Baker 15672 ( ASU0054187 ) ; 3 miles east of Ocampo, 1974, Jansen 11 ( ASU0059076 ). Mexico, Durango: Ca. 21 mi W of Ciudad Lerdo (0.7 mi W El Refugio ) (ca. 19 air mi W Torreon) Sierra del Rosario , 1977, Pinkava P-13866 ( ASU0059104 ) ; 5.1 mi S of El Refugio, 21 air mi SW Torreon, 12.3 mi from MEX 40, Efacing steep mountain cliffs above Rio Nazas. Pass through E edge of Sierra del Rosario, 1977, Pinkava P-13864 ( ASU0059120 ) ; Rte 40, ca. 20 mi S of Leon Guzman plaza. Microondas Chocolate Station turnoff, Pinkava P-13458 ( ASU0059073 ) .

Figures

FIGURE 7. Holotype of Grusonia pulvinata.

FIGURE 8. Grusonia pulvinata: (a) joint; (b) flower; (c) dry fruit; (d) seed; (e) microphotograph of a mitotic metaphase plate (2n = 22).