Linum longipes 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 : 156-157

Linum longipes Rose (1906: 117) . ( Fig. 7a ).

Type:— MEXICO. Guerrero: In mountains near Iguala , Pringle 9261 (holotype US!, isotypes GH!, MICH!, MSC) .

Description: — Herbs, annual, thin, 22–34 cm in height; glabrous, except for a few short hairs near the nodes and the base of branches; root thin; stems erect, simple, unbranched to the middle part, essentially glabrous. Leaves entire; basal leaves arranged in whorls of 4, obovate; distal leaves alternate, ovate; (5.3)14.0–18.0 × (2.5)7.5–9.0 mm, petioles 0.1–1.0(2.0) mm long, apex obtuse; 1-nerved, prominent on the abaxial surface; slightly rough, glabrous; stipular glands present at the base, but not well developed. Inflorescence a widely open cymose panicle occupying half or more of the plant height, pedicels 7.0–17.0 mm long; bracts 2.0- 2.8 mm long, margin entire, apex acute-acuminate, stipular glands absent; sepals persistent, ovate, 2.0–2.5(2.7) × 0.8–1.2 mm, margin entire or with minute glands, apex acuminate, 3-nerved, stipular glands absent; petals yellow, obovate, 4.0 mm long, glabrous; stamens 3.0–4.0 mm long; anthers 0.4 mm long, light yellow; staminodia present; styles fused to near the apex, 1.7–2.3 mm long; stigmata capitate, yellow. Fruit widely ovoid, light yellow, 1.8–1.9 × 1.2–1.9 mm, glabrous, pericarp thin, apex apiculate, dehiscent into 10 segments, false septa incomplete with some marginal hairs; seeds elliptical, light brown, whitish cover, 0.4-0.6 × 1.0– 1.1 mm.

Distribution: —Endemic to Mexico, in Guerrero, Morelos, and Puebla ( Fig. 2a ).

Habitat and ecology: —Oak forests, low deciduous tropical forest. Elevation 700–1600 m. Cambisol, Lithosol, and Rendzina soil types.

Phenology:—Flowering and fruiting in October.

Note: — Linum longipes shares a similar morphology with L. cruciata ; however, when reviewing the herbarium material, longer pedicels, glabrous, and fused styles are observed as unequivocal characters of L. longipes . Besides, the species shows the unique trait of a few minute hairs near all nodes and at the base of branches.

Conservation status: — Linum longipes has an EOO of 416.473 km 2 and an AOO of 16 km 2. In addition to being endemic, the species is known from <5 localities, thus fulfilling the necessary criteria ( IUCN 2019) to be considered as EN (B1 + 2ac(iii)). Therefore, this species is endangered in the wild.

Specimens examined: — MEXICO. Guerrero: Iguala, Mountains near Iguala , 1514 m, 18°22’46.23”N, 99°28’25.71”W, 11 October 1900, C.G. Pringle 9261 ( MEXU!) . Morelos: Jojutla, Cerro del Higuerón , 750 m, 14 October 1984, I. Rivera 25 (MEXU!, UAMIZ!) . Puebla: Izúcar de Matamoros , 2 October 1942, F. Miranda 2222 ( MEXU!) ; Izúcar de Matamoros, Tropical Deciduous Forest at Puerto Las Palmas , 1525 m, 12 October 1986, D.E. Breedlove & F. Almeda 65221 ( MEXU!) ; Izúcar de Matamoros, Carretera Izúcar-Huajuapan de León , 1300 m, 18°31’33”N, 98°25’05”W, 30 October 1994, J.L. Panero et al. 5302 ( 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 7. A. Linum longipes; B. Linum mexicanum; C. Linum nelsonii; D. Linum neomexicanum. Photography by José Luis Colin.