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 elongatum (Small) H.J.P.Winkler (1931: 116) . ( Fig. 6a ). Type:— UNITED STATES OF AMERICA . Texas : Laredo, Reverchon 3776 (originally cited as Bush 3776 ) ( holotype NY!, isotypes MO, US !) . Cathartolinum elongatum Small (1907f: 82) . Description: — Herbs , annual, occasionally perennial, 15–30 cm in height, glabrous, root thick; stems erect to ascending, striate, branched from the base, branches diffuse, glabrous. Leaves entire, sometimes glandular, alternate, linear, 5.0–25.0 × 0.5–1.0(1.5) mm, sessile, apex acute; 1-nerved, nervation more evident in the abaxial surface, scariose; glabrous, stipular glands present, sometimes only at the base of distal leaves. Inflorescence a cymose panicle, pedicels 5.2–10.4 mm long; bracts 3.2–6.3 mm long, margin dentate, apex acuminate, with stipular glands present at the base; sepals deciduous, lanceolate, 6.0–11.0 × 1.4–1.8 mm , margin glandular-dentate, apex attenuate, 3-nerved, stipular glands absent; petals yellow-orange to salmon or brownish-red, wine-red base, widely obovate, 14.0–18.0 mm long; stamens 5.0–6.0 mm long; anthers 1.5–2.5 mm long, brick-red; staminodia absent; styles fused to near the apex, 7.0– 9.5 mm long; stigmata capitate, gray to wine-red. Fruit ovoid, yellow, 4.0–4.3 × 3.0– 3.7 mm , glabrous, pericarp thick, apex obtuse, dehiscent into 5 segments; seeds narrowly elliptical, reddish-brown, 2.3–3.0 × 1.2–1.3 mm . FIGURE 6. A. Linum elongatum ; B. Linum flagellare ; C. Linum lasiocarpum ; D. Linum lewisii . Photographs by José Luis Colin. Distribution: — United States of America ; in Mexico , in Tamaulipas ( Fig. 5b ). Habitat and ecology: —Thorny shrubland. Elevation 0–300 m . Compact sandy soils, Xerosol type . Phenology: —Flowering in February–May; fruiting in March–August. Note: —In its habitat, during the flowering period, the species is easily recognized due to the color of its petals with their distinctive wine-red-colored band near the center, brick-red anthers and wine-red to gray stigmata, which together provide diagnostic characters. The stems of the species are strongly striate. Conservation status: — Linum elongatum is known only from a narrow area of Texas and northern Mexico . One locality is known from Mexico , in the state of Tamaulipas , which may suggest some vulnerability. With only these data, it is not possible to carry out a conservation assessment. Therefore, to explore its probable threat category, it was necessary to integrate the records of GBIF. According to the B criterion ( IUCN 2019 ), this species is Near Threatened (NT). Thus, it presents an EOO close to 20,000 km ² ( 22,940.563 km 2 ) and AOO < 2000 km ² ( 116 km 2 ), and although only one locality is known in the country, according to the data found in GBIF it is likely that it is found in ≥ 10, so some degree of uncertainty is added. Specimens examined: — MEXICO . Tamaulipas : Nuevo Laredo, Along Hwy 2, 5 mi E of junction with Hwy 85, 28 August 1976 , C.M. Rogers 13477 ( CIIDIR !) .