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

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 : 154

Linum flagellare H.P.J. Winkler (1931: 116) . ( Fig. 6b ).

Type:— MEXICO. Coahuila: Parras, Purpus 1122 (holotype NY!, isotypes F, GH!, MO!, UC) .

Cathartolinum flagellare Small (1907g: 78) .

Linum coahuilense C.M. Rogers (1964b: 279) . Type:— MEXICO. Coahuila. 10 mi W of Saltillo, Correll & Johnston 21403 (LL!).

Description: — Herbs, perennial, 25–40 cm in height, glabrous, glaucous, root thick; stems erect, more or less branched throughout, glabrous. Leaves entire, alternate, basal leaves sometimes opposite, linear to linear-lanceolate, (5.0)11.0– 17.0 × (0.5) 0.7–1.7 mm, sessile, apex slightly acuminate, 1-nerved, coriaceous, glabrous; stipular glands generally absent, sometimes present only in basal leaves. Inflorescence a cymose panicle, more or less diffuse, branches thin, pedicels 2.1–8.3 mm long; bracts 2.2–2.7 mm long, margin entire, apex acuminate; sepals persistent, narrowly lanceolate, 2.0–5.6 × 0.9–1.3 mm; margin scariose, with sparse glandular teeth, apex extremely acute; 1-nerved, stipular glands absent; petals yellow, brownish-red when dried, closely narrow or oblanceolate, 4.0–8.0 mm long, glabrous; stamens 2.0–4.0 mm long; anthers 0.6-1.0 mm long, yellow; staminodia minute, sometimes absent; styles connate at the base to fused to half their length, 1.4–2.4 mm long; stigmata capitate, yellow. Fruit widely ovoid, yellow, 2.4–3.3 × 2.3–2.6 mm, glabrous, pericarp thin, apex pointed, dehiscent into 10 segments, false septa partially developed, septa sparsely ciliate but conspicuous along the margin; seeds elliptical, light brown, 1.6–2.0 × 1.0– 1.2 mm.

Distribution: —Endemic to Mexico, in Coahuila, Nuevo Leon, and Zacatecas ( Fig. 2b ).

Habitat and ecology: —Cardonal shrublands, crassi-rosette-leaved thorny shrublands, oak forests, oak-pine forests, yucca shrublands, thornless or sub-thornless small-leaved shrubland, high or medium sub-evergreen tropical forests, low deciduous thorny tropical forest, sandy arid desert vegetation. Elevation 1400–2250 m. Phaeozem, Lithosol, Regosol, and Xerosol soil types.

Phenology: —Flowering in March–September; fruiting in March–October.

Note: — Linum flagellare is quite variable in terms of habit, flower size, presence of stipular glands, and style attachment. It is usually confused with L. rupestre , which is far more common and with which it shares a similar habit, but from which it can be differentiated by the absence of stipular glands in most leaves, much smaller styles connate at the base or attached to half or almost half its length. In addition, petals exhibit a brownish-red color when dried, a character that persists and is observed in herbarium specimens.

Conservation status: —According to the IUCN (2019) B criterion, L. flagellare is VU (B2abc(iii)), with an EOO of 28,947.347 km 2 and AOO of 36 km 2. It is worth mentioning that according to an evaluation carried out by CONABIO (2021), its habitat is constantly threatened by anthropic activities.

Specimens examined: — MEXICO. Coahuila: Parras, Sierra de Parras , 2000 m, 25°21’00”N, 102°12’00”W, 19 September 1993, G. Nesom et al. 7645 ( MEXU!) ; Saltillo, Suroeste de la Sierra de Zapalinamé , 2013 m, 25°14’32”N, 101°04’13”W, 15 April 2015, J.A. Encina & J.M. Cárdenas V. 4429 ( ANSM!) ; Saltillo, Slope near Las Barrancas, 3 May 1959, D.S. Correll & I.M. Johnston 21403 (CHAPA!, MEXU!) ; Saltillo, Sierra de Zapalinamé , 2245 m, 25°15’26”N, 101°03’19”W, 16 August 2014, J.A. Encina et al. 3903 ( CIIDIR!) ; 1.5 miles SW of Las Delicias , 1615 m, 26°14’00”N, 102°49’00”W, 15 August 1973, J. Henrickson 12476 ( MEXU!) ; 3 km al S de El Frayle , 1953 m, 25°00’47”N, 101°20’06”W, 1 October 2016, M.A. Ayala-Ramos et al. 60 ( MEXU!) ; 30 km WSW of Villa Ocampo , 1600 m, 27°15’00”N, 102°41’00”W, 26 September 1986, J. Henrickson & L. Woodruff 20376 ( MEXU!) . Nuevo Leon: Bustamante, Bustamante Canyon , 496 m, 26°32’58.45”N, 100°33’18.68”W, 13 August 1988, T.F. Patterson 6591 ( TEX!) . Zacatecas: Concepción del Oro, km 199 de la carretera Zacatecas-Saltillo , 1850 m, 7 May 1977, J. García P. 316 ( CHAPA!) ; 2.5 miles NNE of Estación Camacho , 1860 m, 24°47’00”N, 102°13’00”W, 25 September 1973, J. Henrickson 13520 ( MEXU!) ; 5 km by road WSW of Caopas , 1940 m, 24°46’00”N, 102°12’40”W, 28 March 1973, M.C. Johnston et al. 10453 ( MEXU!) ; 7.5 km by road WSW of Caopas on road to Camacho , 1890 m, 24°45’20”N, 102°13’30”W, 28 March 1973, M.C. Johnston et al. 10449 ( MEXU!) .

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 6. A. Linum elongatum; B. Linum flagellare; C. Linum lasiocarpum; D. Linum lewisii. Photographs by José Luis Colin.