Linum rupestre Engelmann (1850: 232)

González-Velasco, Juan, Burgos-Hernández, Mireya, Galván-Escobedo, Iris G. & Castillo-Campos, Gonzalo, 2022, Taxonomic update of the flax family in Mexico, Phytotaxa 549 (2), pp. 141-184 : 166-167

Linum rupestre Engelmann (1850: 232) . ( Fig. 9d ).

Type:— UNITED STATES OF AMERICA. Texas: New Braunfels, Lindheimer 337 (holotype GH!, isotypes MO!, NY!, PH!, UC, US!, YU!) .

Linum rupestre var. cymosulum Engelmann (1852a: 26) . Type:— MEXICO. Coahuila: Buena Vista, J. Gregg 63; 1847 (Holotype: MO!)

Cathartolinum rupestre Small (1907d: 76) .

Cathartolinum wrightii Small (1907d: 76) . Type:— UNITED STATES OF AMERICA. Texas: from western Texas to El Paso, C. Wright 71 (holotype NY!, isotypes GH!, UC, US!)

Linum wrightii H.J.P. Winkler (1931: 116) .

Description: — Herbs, perennial, 25–50(75) cm in height, glabrous, sometimes sparsely pubescent in the basal portion, root thin; stems erect, thickened, striate, unbranched up to the level of the inflorescence, essentially glabrous. Leaves entire, sometimes slightly dentate; basal leaves alternate or opposite, distal leaves alternate; linear to linear-lanceolate, 4.0–26.0 × (0.3) 0.5–2 mm, sessile; apex acute to acuminate, whitish; 1-nerved, coriaceus, glabrous, stipular glands present at the base. Inflorescence a cymose panicle, pedicels 2.4–21.0 mm long; bracts 2.2–5.5 mm long, margin glandular-dentate; apex acuminate, whitish; stipular glands at the base, conspicuous, black; sepals persistent, lanceolate to ovate, (2.4)2.5–5.0 × 0.8–1.2(1.5) mm, generally with a dark wine-red color; margin glandular-dentate, occasionally scariose; apex acuminate to cuspidate, whitish tip, 1-3-nerved, conspicuous nerves, glabrous, stipular glands present at the base; petals yellow, oblanceolate or obcordate, 6–11 mm long, pubescent near the base; stamens 2.0–8.0 mm long; anthers 0.5–1 mm long, yellow; staminodia present, minute; styles free, 3.0– 6.5 mm long; stigmata capitate, yellow. Fruit widely ovoid, yellow, 1.8–2.4 × (1.0)2.0–3.0 mm, glabrous, pericarp thin, apex acute, dehiscent into 10 segments, false septa partially developed, septa with marginal cilia; seeds ovate to widely oblong, reddish-brown, 1.2–1.6 × 1.0 mm.

Distribution: — United States of America; in Mexico, in Aguascalientes, Chiapas, Chihuahua, Coahuila, Durango, Guanajuato, Nuevo Leon, Oaxaca, Puebla, Queretaro, San Luis Potosi, Tamaulipas, Zacatecas, and Veracruz ( Fig. 2a ).

Habitat and ecology: —Deciduous forest, cypress-juniper forest, cardonal shrublands, chaparral shrubland, crassirosette-leaved thorny shrublands, oak forests, oak-pine forests, yucca shrublands, thorny shrubland, thornless or subthornless small-leaved shrubland, prickly-pear cacti shrublands, palm-tree forests, grasslands, low deciduous tropical forest, low deciduous thorny tropical forest, sandy arid desert vegetation, zacatonal alpine grasslands. Elevation 1200– 3000 m. Limestone Andosol, Cambisol, Kastanozem, Phaeozem, Lithosol, Luvisol, Regosol, Rendzina, Solonchak Vertisol, Xerosol, and Yermosol soil types.

Phenology:—Flowering and fruiting in September–December.

Note: —Its narrow leaves and absence of foliar whorls are traits that allow differentiating L. rupestre from its closest related species. The morphology resembles L. scabrellum , with which it is usually confused; however, L. rupestre is glabrous. It also resembles L. flagellare in habit, but the presence of stipular glands in leaves and sepals, as well as the free and much longer styles in L. rupestre , allow differentiating it from the latter.

Conservation status: — Linum rupestre is one of the most widely distributed Linum species in Mexico, with a recorded EOO of 596,195,131 km 2 and AOO of 220 km 2. This, together with its presence in various environments in the country, means that it can be considered as LC.

Specimens examined: — MEXICO. Aguascalientes: Tepezalá , 4 km al E de Tepezalá, 2000 m, 11 September 1980, M. De la Cerda & G. García 276 ( CIIDIR!) ; Tepezalá , 2 km al E de Tepezalá, 2200 m, 22°13’28”N, 102°08’14”W, 29 May 2009, G. García 5581 ( CIIDIR!) ; Tepezalá, Arroyo Las Pilas , 2024 m, 22°15’59”N, 102°10’30”W, J. Martínez-Ramírez 2570 ( INEGI!) ; Tepezalá, 500 m al NE de la cementera Cruz Azul , 2034 m, 22°11’27.66”N, 102°11’53.98”W, 1 February 2013, J. Martínez R. 2295 ( INEGI!) ; Tepezalá , 4 km al E de Tepezalá, 2247 m, 22°13’13.1”N, 102°08’6.1”W, 19 April 2013, Araiza-Arvilla 346 ( INEGI!) . Chiapas: Oxchuc, Tolbil Ja´ , 3000 m, 16°49’51”N, 92°15’50”W, 20 June 1988, F. Goméz-Santiz 244 ( XAL!) . Chihuahua: Chihuahua, 2.0 mi NE of Aquiles Serdán, Sierra Santa Eulalia , 1530 m, 28°30’00”N, 105°52’0.01”W, 19 July 1977, E. Lehto 21539 ( ASU!) . Coahuila: Arteaga, Sierra de Zapalinamé , 1928 m, 25°24’51”N, 100°50’10”W, 15 July 2015, J.A. Encina & J.M. Cárdenas V. 4913 (ANSM!, MEXU!) ; Candela, Sierra de Pájaros Azules Campo Santa María , 1800 m, 27°01’00”N, 100°50’00”W, 11 January 1997, M.A. Carranza et al. 2730 (ANSM!, XAL!) ; Castaños, Sierra La Gavia Rancho La Gavia , 1295 m, 26°10’00”N, 101°18’30”W, 10 August 1995, M.A. Carranza & J. Encinas 2263 (CHAP!, CIIDIR!, XAL!) ; Cuatrociénegas, Rancho Potrero Menchaca , 1300 m, 1 May 1981, L.E. Rodríguez G. 154 ( ANSM!) ; General Cepeda, Sierra de la Paila , 1750 m, 25°38’00”N, 101°35’00”W, 24 May 1990, J.A. Villarreal et al. 5640 (ANSM!, CHAPA!) ; General Cepeda, Sierra de la Paila, parte Oeste , 1560 m, 26°05’00”N, 101°44’00”W, 18 April 1992, J.A. Villarreal et al. 6349 ( ANSM!) ; General Cepeda, Sierra de la Paila valle de La Nopalera , 1750 m, 25°38’00”N, 101°35’00”W, 27 April 1990, J.A. Villarreal et al. 5620 ( ANSM!) ; Monclova, On Route 30, west of Monclova , 22 December 1977, N.A. Harriman 14218 ( CHAPA!) ; North flank of Sierra de los Alamitos , 1400 m, 26°30’00”N, 102°21’00”W, 14 June 1972, F. Chiang et al. 7772 ( MEXU!) ; Ocampo, Sierra la Encantada, Rcho. Puerto del Aire , 1250 m, 28°17’00”N, 102°28’00”W, 8 September 1990, M.A. Carranza et al. 743 ( ANSM!) ; Parras, Arroyo seco en el Rancho El Tunal , 2020 m, 25°21’00”N, 101°59’30”W, 16 April 1981, A. Rodríguez & M.A. Carranza 205 ( ANSM!) ; Parras, Rancho El Tunal , 2050 m, 25°20’00”N, 101°55’00”W, 7 October 1983, A. Rodríguez & M. Carranza 917 (ANSM!, CIIDIR!) ; Parras, Sierra de Parras en el arroyo seco del Rancho El Tunal , 2050 m, 1 September 1981, A. Rodríguez & P. Antonio H. 564 ( ANSM!) ; Parras, Arroyo seco en el Rancho El Tunal , 2050 m, 25°21’00”N, 101°59’30”W, 16 April 1981, A. Rodríguez & M.A. Carranza s.n. ( CIIDIR!) ; Ramos Arizpe, El Cedral Sierra de la Paila , 1600 m, 26°02’00”N, 101°23’00”W, 16 October 1986, J.A. Villarreal et al. 3551 ( ANSM!) ; Ramos Arizpe, Sierra de la Paila Ejido el Cedral , 1900 m, 25°57’00”N, 101°33’00”W, 4 October 1989, J.A. Villarreal et al. 5249 ( ANSM!) ; Ramos Arizpe, Cañada el Diente Sierra de la Paila , 1600 m, 26°09’00”N, 101°30’00”W, 5 October 1988, J.A. Villarreal & M.A. Carranza 4696 ( ANSM!) ; Ramos Arizpe, Cañada el Diente Sierra de la Paila , 1600 m, 26°09’00”N, 101°30’00”W, 19 September 1989, J.A. Villarreal & M.A. Carranza 5217 ( ANSM!) ; Ramos Arizpe, El Cedral Sierra de la Paila , 1600 m, 26°02’00”N, 101°23’00”W, 20 August 1987, J.A. Villarreal & M.A. Carranza 3928 (IBUG!, MEXU!) ; Saltillo, Entrada Cañón de San Lorenzo , 1974 m, 25°20’22”N, 100°59’10”W, 26 April 2015, J.A. Encina & J.M. Cárdenas V. 4654 ( ANSM!) ; Saltillo, Ladera baja de la Sierra de Zapalinamé , 2051 m, 25°19’47”N, 101°00’47”W, 25 August 2007, J.A. Encina et al. 1905 ( ANSM!) ; Saltillo, El Chiflón , aprox. 35 km al NW de Saltillo, 1400 m, 25°27’36”N, 101°19’07”W, 28 July 1998, M.A. Carranza & J. Valdés R. 2958 ( ANSM!) ; Saltillo, Rancho Los Ángeles , 1900 m, 28 July 1982, G. Villaseñor et al. 1633 ( ANSM!) ; Saltillo, Estación de Microondas Vega , 1600 m, 25°26’00”N, 101°06’00”W, 5 June 1992, J.A. Villarreal et al. 6625 ( ANSM!) ; Saltillo, Rancho “Dos arbolitos”, 1800 m, 15 June 1981, M.A. Carranza et al. s.n. ( ANSM!) ; Saltillo, Oeste de la Sierra de Zapalinamé , 1951 m, 25°20’7.19”N, 101°01’2.03”W, 19 April 2015, J.A. Encina et al. 4482 ( ANSM!) ; Saltillo, Camino del Cuatro Sierra de Zapalinamé , 2330 m, 25°21’35”N, 100°56’08”W, 26 July 2003, J.A. Encina et al. 1139 ( ANSM!) ; Saltillo , S de Saltillo camino a Zacatecas, 1 km al N de La Minita , 2015 m, 25°09’28.6”N, 101°05’52”W, 1 October 2016, M.A. Ayala-Ramos et al. 57 ( MEXU!) . Durango: El Mezquital, 5 km al NW de Yonora , 2020 m, 23 May 1987, M. González & S. Acevedo 2214 (ANSM!, CIIDIR!, IEB!) ; El Mezquital , 48 km de Durango, 21 April 1981, Y. Herrera 43 ( CIIDIR!) ; Nombre de Dios , 3 km al W de La Parrilla, 14 November 1983, S. González et al. 2800 (CHAP!, CHAPA!, CIIDIR!, IBUG!) . Guanajuato: Comonfort , 2 k al NE de Empalme Escobedo, 1900 m, 27 June 1987, Rzedowski 43440 (CIIDIR!, IBUG!, XAL!) ; San Miguel de Allende, Atotonilco , 1900 m, 8 October 1992, Rzedowski 51740 ( XAL!) ; San Miguel de Allende , 17 km al NW de San Miguel de Allende, 1900 m, 23 August 1988, Rzedowski 47143 ( XAL!) ; Xichú, Llano Grande 10 km al Este de Xichú , 1500 m, 14 September 1989, E. Ventura & E. López 7322 ( XAL!) . Nuevo Leon: Aramberri, near to San Francisco , 1750 m, 01 June 1997, Hinton et al. 27060 ( ANSM!) ; Aramberri, km. 5 Carretera La Escondida-Aramberri , 1400 m, 24°06’19”N, 99°53’55”W, 26 August 2005, P. Carrillo-Reyes & V. Sosa, 4654 ( IBUG!) ; Cadereyta, Ca. 4 km al NE de Cadereyta Jiménez, 20 April 1973, J. Marroquín 2518 ( ANSM!) ; Dr. Arroyo, Santa Gertrudis, nr., 1780 m, 16 March 1993, Hinton et al. 22708 ( ANSM!) ; Galeana , Cerro El Potosí, SE of., 2210 m, 23 July 1983, Hinton et al. 18526 (ANSM!, CHAPA!, CIIDIR!, IBUG!, XAL!) ; Dr. Arroyo, Matehuala-Dr. Arroyo aprox. 38 km, 17 June 1992, J.A. Villarreal & M.A. Carranza 6554 ( ANSM!) ; Galeana, El Barrial, 1620 m, 24 September 1979, Hinton et al. 17662 ( IEB!) ; Zaragoza, Zaragoza , nr., 1365 m, 28 July 1993, Hinton et al. 23115 ( ANSM!) ; Zaragoza, Sierra El Soldado , 2850 m, 24°48’00”N, 99°52’00”W, 24 August 1989, J.A. Villarreal et al. 4920 ( ANSM!) . Oaxaca: Cuicatlán, 16 km al W por la terracería que va rumbo a San Pedro Jocotipac , 1750 m, 19 August 1987, A. Salinas T. 4323 ( IEB!) ; San Pedro Jocotipac, Loma de En medio 5 km al SE de San Pedro Nodon, 1910 m, 24 October 1991, P. Tenorio L. & E. Martínez 17903 ( MEXU!) . Puebla: Chapulco, 2 km antes de llegar a Nicolas Bravo , 2300 m, 28 September 1989, M. Chazaro B. et al. 6094 ( XAL!) . Queretaro: Jalpan de Serra, Cerro de los Fresnos , 1500 m, 4 September 1989, C. Guzmán 107 ( IEB!) . San Luis Potosi: Catorce, San Antonio , 2146 m, 23°31’34.75”N, 100°56’16.35”W, 13 October 2016, J. López H. 77 ( INEGI!) ; Charcas, Camino Charcas-Villa de Cos , 2215 m, 23°09’49.6”N, 101°10’54.9”W, 13 September 2020, A. Villalvazo-Hernández & J. González-Velasco 54 ( CHAPA!) ; Charcas, Sierra de Monte Grande , 2175 m, 14 September 1989, J.A. Reyes A. 460 (CHAP!, CHAPA!, IBUG!) ; Charcas, Sierra de Monte Grande , 2175 m, 26 October 1989, J.A. Reyes A. 923 (CHAPA!, IEB!, SLPM!) ; Charcas, Sierra de Monte Grande , 2500 m, 13 September 1989, J.A. Reyes A. 392 ( CHAPA!) ; Charcas, Sierra de Monte Grande , 2175 m, 23 October 1989, J.A. Reyes A. 875 ( CHAPA!) ; Charcas, Sierra de Monte Grande , 2300 m, 14 September 1989, J.A. Reyes A. 427 ( CHAPA!) ; Moctezuma, “La Calera” 2.5 km al Oeste del Estanco , 1980 m, 20/August/1976, M. Bustos Z. s.n. ( CHAPA!) . Tamaulipas: Víctoria , ca 17 mi by rd SW of Cd. Víctoria, 1086 m, 23°36’00”N, 99°12’00”W, 31 July 1976, G.L. Webster & W.S. Armbruster 20567 ( TEX!) . Veracruz: Totalco , 4 km al SW de Alchichica, 235 m, 19 May 1975, M. Vázquez-Torres et al. 1968 ( CIB!) ; Perote, Perote , 19°19.3’00”N, 97°13’35.79”W, 2494 m, 19 December 1998, G. Castillo-Campos 19099 ( XAL!) . Zacatecas: Jerez, A 2 km al Noreste de la comunidad de Puerta de Chula , 2130 m, 22°42’8.13”N, 102°52’54.81”W, 15 October 2020, L. Hurtado-Reveles 674 ( CHAPA!) .

Figures

FIGURE 2. Geographic distribution in the Mexican territory of: A. H. micranthum, L. aristatum, L. berlandieri var. filifolium, L. longipes, and L. rupestre; B. L. australe, L. australe var. glandulosum, L. flagellare, L. nelsonii, and L. usitatissimum. Maps by Ma. Isabel Olivares.

FIGURE 9. A. Linum orizabae; B. Linum pringlei; C. Linum puberulum; D. Linum rupestre. Photographs by José Luis Colin.