Taxonomic update of the flax family in Mexico Author González-Velasco, Juan 0000-0001-8743-3906 Departamento de Botánica, Colegio de Postgraduados. km 36.5 carretera México-Texcoco, Montecillo, 56230 Texcoco, Mexico, Mexico. & gonzalez. juan @ colpos. mx; https: // orcid. org / 0000 - 0001 - 8743 - 3906 gonzalez.juan@colpos.mx Author Burgos-Hernández, Mireya 0000-0003-3036-297X Departamento de Botánica, Colegio de Postgraduados. km 36.5 carretera México-Texcoco, Montecillo, 56230 Texcoco, Mexico, Mexico. & burgos. mireya @ colpos. mx; https: // orcid. org / 0000 - 0003 - 3036 - 297 X burgos.mireya@colpos.mx Author Galván-Escobedo, Iris G. 0000-0003-4250-4971 Departamento de Botánica, Colegio de Postgraduados. km 36.5 carretera México-Texcoco, Montecillo, 56230 Texcoco, Mexico, Mexico. & igalvan @ colpos. mx; https: // orcid. org / 0000 - 0003 - 4250 - 4971 igalvan@colpos.mx Author Castillo-Campos, Gonzalo 0000-0002-3059-8109 Red de Biodiversidad y Sistemática. Instituto de Ecología A. C. Carretera antigua a Coatepec km. 351, El Haya, 91073, Xalapa, Veracruz, Mexico. & gonzalo. castillo @ inecol. mx; https: // orcid. org / 0000 - 0002 - 3059 - 8109 gonzalo.castillo@inecol.mx text Phytotaxa 2022 2022-06-08 549 2 141 184 journal article 67684 10.11646/phytotaxa.549.2.3 62e44cf6-6f9d-4658-a89b-a0ddf687b5b9 1179-3163 6622753 Linum berlandieri var. filifolium (Shinners) C.M. Rogers (1984a: 39) . ( Fig. 3c ). Type :— UNITED STATES OF AMERICA . Texas : Brewster County , McVaugh 7798 ( holotype SMU, isotypes F, GH!, MICH) . Linum rigidum var. filifolium Shinners (1949: 136) . FIGURE 4. Linum australe var. glandulosum . A. Aspect general of the plant; B. Leaf; C. Flower; D. Filament and anther; E. Styles and stigmata; F. Fruit; G. Detail of stipular glands. Illustrated by Lizbeth Pérez Lucas, based on A. Ventura A. 1727 & M.L. Arreguín 346 . Description: — Herbs , annual, occasionally perennial, 5–40 cm in height, hirsutulose near the base; root thin; stems erect, extended, ascending, striate, branching from the base, essentially glabrous, hirsutulose at the base. Leaves entire or distal leaves with few tiny marginal teeth, basal leaves opposite or alternate, distal leaves alternate; linear to linearlanceolate, (4.5)10.0–25.0 × (0.5)1.0–4.0 mm, the largest near or above the middle part of the stem; sessile, apex acuminate, 3-nerved, scariose, glabrous, stipular glands small present at the base. Inflorescence a cymose panicle, dense, pedicels 2.8–4.5 mm long, striate; bracts 3.8–6.3 mm long, margin with few minute teeth, apex acuminate, whitish, stipular glands at the base; sepals deciduous, lanceolate, (4.9)6.0–12.0 × 1.2–1.5 mm , margin with prominent glandular teeth, sometimes scariose; apex acute or attenuated, usually 3-nerved, glabrous, stipular glands absent; petals yellow-orange, reddish to brick-red below the middle portion, widely obovate, 11.0–19.0 mm long, glabrous; stamens 4.0–9.0 mm long; anthers 1.0–2.0 mm long, yellow; staminodia absent; styles fused to near the apex, 6.0–9.0 mm long, yellow; stigmata capitate, dark brown. Fruit widely ovoid to triangular-ovoid, yellow, 3.6–4.7 × 3.0–4.0 mm, pericarp thin, translucent, apex obtuse, dehiscent into 5 segments; seeds narrowly ovate, reddish-brown, 2.6–3.4 × 1.0– 1.6 mm . Distribution: — United States of America ; in Mexico , in Chihuahua , Coahuila , and Nuevo Leon ( Fig. 2a ). Habitat and ecology: —Cypress-juniper forest, crassi-rosette-leaved thorny shrubland, oak forests, yucca forests, thornless or sub-thornless small-leaved shrubland, evergreen thorny tropical forest. Elevation 200–1750 m . Sandy, rocky soils, sometimes calcareous belonging to Kastanozem, Phaeozem, Lithosol, Planosol, Regosol, Rendzina, and Xerosol. Phenology :—Flowering and fruiting in March–June. Note: —Only this variety is distributed in Mexico . The presence of bracts with a whitish acuminate apex and the capsular fruit with thin, somewhat translucent pericarp, allows separating L. berlandieri var. filifolium from L. berlandieri var. berlandieri . Conservation status: —According to the criteria established by the IUCN (2019) and its distribution in a few northern states of Mexico , L. berlandieri var. filifolium is EN (B1 + 2ac(iii)) with an EOO < 20,000 km 2 ( 11,601.262 km 2 ) and AOO < 500 km 2 ( 28 km 2 ). Specimens examined: — MEXICO . Chihuahua : Manuel Benavides , Sierra Rica arroyo El Pedregoso , 1743 m , 29°10’12”N , 104°02’58”W , A. Juárez P. 165 (MEXU!, SLPM !) . Coahuila : Villa Acuña , Serranias del Burro Rcho El Bonito , 29°01’30”N , 102°07’30”W , 4 May 1981 , D.H. Riskind 2362 ( ANSM !) ; 2.5 km of Rancho El Jardin on the road toward Mina El Popo , 1600 m , 29°07’00”N , 102°40’00”W , 28 July 1973 , M.C. Johnston et al. 11840 ( MEXU !) ; 5.2 rd miles NW of Rancho El Jardin towars Mina Popo , 1645 m , 29°09’00”N , 102°43’00”W , 2 July 1973 , J. Henrickson & B. Prigge 11460 ( MEXU !) ; 17 miles S of Allende along Hwy 57, 500 m , 28°12’00”N , 101°05’00”W , 3 May 1977 , J. Henrickson & E. Lee 16025 ( MEXU !) ; 22 km ESE of La Cuesta del Plomo on the Múzquiz-Boquillas highway, 1000 m , 28°38’38”N , 102°18’18”W , 7 June 1972 , F. Chiang et al. 7543 ( MEXU !) ; 52 miles SE of Big Bend National Park basin in the S end of the Sierra Maderas del Carmen in Cañon del Alamo , 1450 m , 28°52’00”N , 102°34’00”W , 5 August 1976 , J. Henrickson & B. Prigge 14916 ( MEXU !) . Nuevo Leon : Hwy. 85, ca. 4 mi. SW of Nuevo Laredo , 14 November 1958 , R.C. Rollins & R.M. Tryon 5802 ( MEXU !) .