Linum nelsonii Rose (1906: 117)

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 : 160-161

Linum nelsonii Rose (1906: 117) ( Fig. 7c ).

Type:— MEXICO. Veracruz : municipality of Orizaba, Boca del Monte , E. W. Nelson 210 (Holotype: US!) .

Description: — Herbs, perennial, occasionally annual, 17–65 cm in height, glabrous or sparely pubescent, root thin; stems erect to decumbent, commonly unbranched up to the inflorescence, essentially glabrous. Leaves, basal entire or ciliated, arranged in whorls of 4–6; distal glandular-dentate, alternate or opposite, ovate to obovate; 4.0–18.0(– 21.0) × 2.0–12.0 mm, decreasing to the inflorescence, sessile, apex obtuse to rounded or acute in distal leaves; 3–5- nerved, central nerve prominent; smooth, glabrous or with scattered pubescence, stipular glands present at the base. Inflorescence a cymose panicle, pedicels 3.0–12.0 mm long, rarely pubescent, whitish hairs; bracts 3.5–10.0 mm long, margin denticulate, apex acuminate, stipular glands present at the base; sepals persistent, lanceolate to narrowly lanceolate or narrowly ovate, 2.5–4.0 × 1.0–2.0 mm, margin glandular-dentate, apex acute to acuminate; 1–(3)-nerved, central nerve prominent; sparsely pubescent, occasionally with stipular glands present at the base; petals yellow-green, oblanceolate to obovate, 3.0–5.0 mm long, glabrous; stamens 2.0–4.0 mm long, villous at the base; anthers 0.6–1.0 mm long, light yellow; staminodia small; styles free, 1.7–4.0 mm long; stigmata capitate, yellow. Fruit widely ovoid, yellow, 1.4–2.0 × 1.5–2.0 mm, pericarp thin, apex acute pubescent, dehiscent into 10 segments, false septa partially developed, septa occasionally with marginal cilia; seeds oblong to ovate, reddish-brown, 0.8–1.3 × 0.5–0.7 mm.

Distribution: —In Mexico, in Chiapas, Coahuila, Guanajuato, Hidalgo, Nayarit, Nuevo Leon, Oaxaca, Puebla, Queretaro, San Luis Potosi, Tamaulipas, and Veracruz ( Fig. 2b ); to Guatemala, Honduras, and Nicaragua.

Habitat and ecology: —Deciduous forest, cypress-juniper forest, oak forests, oak-pine forests, chaparral shrubland, mangrove forest, thorny shrubland, thornless or sub-thornless small-leaved shrubland, pine forests, low deciduous tropical forest, medium or low evergreen tropical forest. Elevation 550–2400 m.Andosol,Acrisol, Cambisol, Phaeozem, Lithosol, Luvisol, Regosol, Rendzina, Vertisol, and Xerosol soil types.

Phenology: —Flowering in February–November; fruiting in April–November.

Note: —According to Rzedowski & Calderón de Rzedowski (1994), the type locality is probably in the state of Puebla. Although L. nelsonii is frequently confused with L. schiedeanum , L. nelsonii can be consistently differentiated from the latter by its pubescent pedicels and stipular glands present at the base of bracts and occasionally in sepals.

Conservation status: —Although according to the criterion B2 established by the IUCN (2019), L. nelsonii can be considered as endangered because of presenting an AOO of 80 km 2, its EOO (496,346.970 km 2) exceeds the value necessary for a threatened category. Therefore, this species is LC given its wide distribution and number of known localities inside and outside the country.

Specimens examined: — MEXICO. Chiapas: Comitán, km17, carretera Comitán, 3 Lagunas , 1781 m, 16°17’39”N, 92°15’59”W, 2 September 2008, G. López V. 1230 ( XAL!) ; Oxchuc, Tz´unun , a 3 km de la escuela por el lado sur, 2400 m, 13 March 1988, F. Gómez S. 19 ( MEXU!) ; Oxchuc , 8 km al norte de Oxchuc, 2400 m, 12 May 1988, F. Gómez S. 164 ( MEXU!) . Coahuila: Castaños, Sierra La Gavia , 1295 m, 26°10’00”N, 101°18’00”W, 10 August 1995, M.A. Carranza y J. Encinas 2261 ( ANSM!) ; Castaños, Sierra La Gavia , 1500 m, 26°10’00”N, 101°18’00”W, 25 October 1995, J.A. Villarreal & M.A. Carranza 8363 ( ANSM!) ; Ramos Arizpe, Sierra de La Paila , 1600 m, 25°58’00”N, 101°32’00”W, 2 November 1988, J.A. Villarreal et al. 4739 ( ANSM!) . Guanajuato: San Luis de la Paz, La Ventana, cerca de Mesas de Jesús , 2000 m, 24 March 1990, E. Ventura & E. López 7837 ( XAL!) . Hidalgo: Molango , 5-6 km al N de Ismolintla, 1900 m, 20°46’37.23”N, 98°43’59.95”W, 27 April 1981, R. Hernández et al. 5893 ( MEXU!) . Nayarit: Tepíc, 5 km de la desviación al Rancho La Noria , 1500 m, 21°29’00”N, 104°59’00”W, J.I. Calzada et al. 19192 ( XAL!) . Puebla: Oriental, Zautla , 2000 m, 6 August 1986, F. Ventura A. 22272 ( XAL!) . Nuevo Leon: Galeana, Ca. 13 miles SW of Galeana, 2200 m, 24°43’00”N, 100°12’00”W, 10 September 1999, Henrickson & V. Heuvel 22472B ( ANSM!) ; Santiago, Cola de Caballo , 9 May 1979, J.A. Villarreal 2463 ( ANSM!) . Oaxaca: Eloxotitlán de Flores Magón, Alrededores del Puente de Fierro , 1175 m, 18°09’11.8”N, 96°51’11.7”W, 9 March 2001, Munn-Estrada et al. 856 ( TEX!) . Queretaro: Arroyo Seco, 6 km al E de la Florida , 1260 m, 21°25’48”N, 99°42’06”W, 13 April 2007, S. Zamudio et al. 13698 ( IEB!) ; Jalpan de Serra, 4-5 km al SE de San Juan de los Durán , 1850 m, 24 May 2012, E. Carranza G. 7670 ( ANSM!) ; Jalpan de Serra, Cañada en la ladera O del Cerro Grande , 2110 m, 21°25’56”N, 99°08’46”W, 29 March 2012, G. Aguilar-Gutiérrez et al. 854 (IEB!, XAL!) ; Jalpan de Serra , 4-5 km al sur de La Parada, 1200 m, 18 December 1991, B. Servín 1481 ( IEB!) ; Jalpan de Serra , 2-3 km al poniente de El Saucito, 900 m, 13 March 1991, B. Servín 882 ( IEB!) ; Landa , 2 km al S de El Rincón, 900 m, 2 April 1987, Rzedowski 42916 ( XAL!) ; Pinal de Amoles , 2 km al S de San Pedro Escanela, 1740 m, 22 February 1991, E. Carranza 3035 ( IEB!) ; Pinal de Amoles , 1.5-2 km al W de San Pedro Escanela, 1780 m, 17 April 1990, E. Carranza 2438 ( IEB!) ; Pinal de Amoles, Cerca de Huazmazontla , 1300 m, 12 March 1989, Rzedowski 48399 ( XAL!) . San Luis Potosi: El Naranjo, Vicinity El Salto above El Naranjo , 446 m, 22°35’11.79”N, 99°23’0.59”W, 1 April 1960, J.A. Duke 3675 ( MEXU!) . Sinaloa: Concordia , 4.5 km al SE de La Petaca, 1700 m, 12 February 2000, R. Vega-Aviña & J.A. Gutiérrez-García 10554 ( MEXU!) . Tamaulipas: Hidalgo, Into the Sierra 14.9 mi W of Hotel Santa Engracia, 570 m, 24°01’00”N, 99°34’00”W, 17 April 1988, G. Nesom 6339 ( XAL!) . Veracruz: Huiloapan, Cerro de San Cristóbal , 1300 m, 18°48’00”N, 97°03’00”W, 22 April 1982, J.I. Calzada 8592 ( XAL!) .

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 7. A. Linum longipes; B. Linum mexicanum; C. Linum nelsonii; D. Linum neomexicanum. Photography by José Luis Colin.