Linum australe var. glandulosum C.M. Rogers (1964a: 336)

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 : 149

Linum australe var. glandulosum C.M. Rogers (1964a: 336) . ( Fig. 4 ).

Type:— MEXICO. Durango: Otinapa, Palmer 465 (holotype US!, isotypes F!, GH, MO!, NY!) .

Mesynium australe (C.M. Rogers) W.A.Weber (1984: 3) .

Description:— Herbs with black stipular glands, very prominent on nodes, base of all leaves, bracts, and sepals.

Distribution: — United States of America; in Mexico, in Chihuahua, Mexico City, Durango, State of Mexico, Guanajuato, Puebla, Sonora, and Veracruz ( Fig. 2b ).

Habitat and ecology: —Cypress-juniper forest, oak-pine forests, prickly-pear cactus patches, grasslands, oak forests, thornless small-leaved shrubland, and pine forests. Elevation 1500–2650 m. Montane soils, mainly red-ash Acrisol, Andosol, Cambisol, Phaeozem, Lithosol, Luvisol, and Regosol.

Phenology: —Flowering and fruiting in May–September.

Taxonomic note: —The black and prominent stipular glands of L. australe var. glandulosum on the nodes, leaves, bracts, and sepals make it possible to clearly differentiate this variety of the species.

Conservation status: — Rzedowski & Calderón de Rzedowski (1992) mention that L. australe var. glandulosum is at risk of extinction. However, according to the criteria established by the IUCN (2019) this variety is Vulnerable (VU) (B2abc(iii)), with an EOO of 164,257.374 km 2 and AOO of 28 km 2, known to <10 localities. It is worth mentioning that its distribution in areas that harbor large human population nuclei of the country and the constant loss of habitat ( CONABIO 2021, Rodríguez-Echeverry & Leiton 2021) could be a cause of threat shortly.

Specimens examined: — MEXICO. Chihuahua: Chuhuichupa, near Chuhuichupa , 2148 m, 29°36’36”N, 108°22’48”W, 1 August 1936, H. LeSueur 132 ( MO!) . Mexico City: Milpa Alta, Paraje de Cuauhte , 2650 m, 4 July 1976, A. Ventura A. 1727 ( IEB!) . Durango: Durango, 18 miles west of Durango, 24 July 1964, C.M. Rogers 13183 ( MEXU!) . State of Mexico: Ixtapaluca, Cerro del Pino , 2300 m, 1 November 1972, M.L. Arreguín 346 ( MEXU!) ; Tlalmanalco, Tramo Tlalmanalco-Amecameca , 2260 m, 12 September 1976, J. García P. 199 ( CHAPA!) . Guanajuato: León , 41 km al NE de León, 2450 m, 14 July 1987, J. Rzedowski 43752 ( IEB!) . Puebla: Acatzingo, San Juan Ocozoc , 2110 m, 18°59’00”N, 97°47’00”W, 1 July 1907, G. Arsené 1921 ( MEXU!) . Sonora: Yecora, 0.2 km north of Yecora and road to Agua Blanca , 1540 m, 28°22’46”N, 108°55’37”W, 15 July 1997, A.L. Reina et al. 780 ( MEXU!) . Veracruz: Perote, Sierra entre Mastaloyan y Frijol Colorado , 2650 m, 19°38’00”N, 97°23’00”W, 25 August 1984, G. Castillo C. et al. 3288 ( 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 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.