Linum cruciata Planchon (1848b: 499)

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 : 151

Linum cruciata Planchon (1848b: 499) . ( Fig. 3d )

Type:— MEXICO. Nayarit: Tepic, Sinclair s.n. (holotype K!) .

Cathartolinum cruciata Small (1907e: 77) .

Linum gracilentum M.E. Jones (1929: 148) . Type:— MEXICO. Nayarit: Tepic, M.E. Jones 22882 (isotypes GH, UC, US!) .

Description: — Herbs, perennial, 15–50 cm in height, essentially glabrous, root thin; stems decumbent toward the base, branched from the base, glabrous in the basal part; pilose in the distal part, near nodes and the inflorescence. Leaves, basal ones entire, arranged in whorles of 4; distal ones dentate, alternate, widely ovated or elliptical, 5.4–13.8 × (3.2) 3.3–8.3 mm, sessile or subsessile, petiole villous; apex obtuse to subacute, apiculate; 1-nerved, more evident on the abaxial surface; slightly scariose, glabrous, or sparsely pilose, stipular glands present at the base. Inflorescence a cymose panicle, with extended branches, pedicels villous, (1.5)3.0–6.0 mm long; bracts 1.9–4.3 mm long, margin dentate, with pedunculate glands, apex acute, stipular glands present, black; sepals persistent, lanceolate, sometimes quite narrow, (1.8)2.4–3.0 × 0.4–0.8 mm, margin with conspicuous glandular teeth, apex acute to subacuminate, 3- nerved, central nerve evident, glabrous; petals light yellow, 4.0–6.0 mm long, glabrous; stamens 3.0–4.0 mm long; anthers 0.7–1.2 mm long, light yellow; staminodia minute; styles free, 2.5–4.3 mm long; stigmata capitate, yellow. Fruit widely ovoid, yellow, (1.1)1.3–1.7 × 1.1–2.0 mm, sparsely pilose above the middle portion, pericarp thin, apex acute, dehiscent into 10 segments, false septa poorly developed; seeds widely ovate, brown, 0.8–0.9 × 0.7–0.8 mm.

Distribution: —In Mexico, in Durango, Jalisco, Nayarit, Queretaro, Sinaloa, Sonora, and Tamaulipas ( Fig. 5a ).

Habitat and ecology: —Deciduous forest, oak forests, oak-pine forests, pine forests, high evergreen tropical forests, low deciduous tropical forest, low thorny deciduous tropical forest, low subdeciduous tropical forest. Elevation 1300–1900 m. Cambisol, Lithosol, Regosol, Vertisol, and Xerosol soil types.

Phenology:—Flowering and fruiting in March–July.

Note: —Endemic to Mexico. It is the only species of the genus within its distribution area that has a combination of characters including leaves in whorls and sepals with conspicuous glandular teeth. In addition, L. cruciata presents free styles and short and villous pedicels, which allow differentiating it from L. longipes .

Conservation status: —Although L. cruciata has an EOO of 315,975.629 km 2, its distribution is not continuous, affecting the extent of occurrence of this species. Based on an AOO of 28 km 2 and the number of localities known (<10), this species is considered under IUCN criteria (2019) as VU (B2ac(iii)).

Specimens examined: — MEXICO. Durango: Canelas, 1200 m al Norte de Canelas , 5 March 1986, M. Vizcarra 265 (CHAP!, CHAPA!, CIIDIR!, IBUG!, IEB!, MEXU!, UAMIZ!) ; Steep side canyons of the RíoTamazula , 1300 m, 20 March 1972, D.E. Breedlove 24527 ( ENCB!) . Jalisco: Autlán, Sierra de Manantlán , 1900 m, 19°32’00”N, 104°14’00”W, 23 March 1965, R. McVaugh 23219 ( ENCB!) . Nayarit: Tepíc, near Tepíc , 1588 m, 21°29’18.31”N, 104°56’0.16”W, 5 January 1892, E. Palmer 2013 ( US!) . Queretaro: Jalpan , a 5 km al SE de Jalpan, 1400 m, 1 May 1982, P. Tenorio & R. Hernández 316 ( MEXU!) . Sinaloa: Capadero, Sierra Tacuichamona , 12 february 1940, H.S. Gentry 5583, 5585 ( MEXU!) . Sonora: Alamos, Entre San Bernardino y Chinipas , 1250 m, 27°19.3’00”N, 108°44’00”W, 18 March 1992, G. Ferguson et al. s.n. ( ARIZ!) . Tamaulipas: 3 km al Sureste de Puerto Purificación , 2 June 1990, F. González M. et al. 17402 ( MEXU!) ; 7 km al Sureste de Puerto Purificación , 6 June 1990, F. González M. et al. 17467 ( MEXU!) .

Figures

FIGURE 3. A. Linum aristatum; B. Linum australe; C. Linum berlandieri var. filifolium; D. Linum cruciata. Photographs by José Luis Colin.

FIGURE 5. Geographic distribution in the Mexican territory of:A. L. cruciata, L. lasiocarpum, L. lewisii, L. mexicanum, and L. tenellum; B. L. elongatum, L. neomexicanum, L. puberulum, L. rzedowskii, and L. schiedeanum; C. L. modestum, L. orizabae, L. pringlei, L. scabrellum, and L. vernale. Maps by Ma. Isabel Olivares.