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southern flax

flax

Habit Herbs, annual, 10–50 cm, puberulent near base, otherwise glabrous. Herbs or subshrubs, annual, biennial, or perennial, glabrous or hairy.
Stems

stiffly ascending-spreading, few to many-branched.

usually erect or spreading to ascending, sometimes decumbent or ascending from decumbent base, unbranched or branched at base, throughout, or only in inflorescence.

Leaves

alternate, appressed;

stipular glands present at basal nodes or throughout;

blade linear, 7–20 × 0.5–l.9 mm, margins entire, not ciliate, apex aristate.

sometimes falling early, alternate or sometimes partially opposite or whorled;

stipular glands present or absent;

blade linear, linear-lanceolate, linear-oblanceolate, lanceolate, oblanceolate, elliptic, oblong, obovate, spatulate, or awl-shaped, margins glandular-toothed or entire, sometimes ciliate.

Inflorescences

racemes.

usually panicles, racemes, or cymes, rarely thyrses or corymbs.

Pedicels

3–15 mm.

articulated or not.

Flowers

sepals deciduous, lanceolate to narrowly ovate, 4–7 mm, margins scarious, delicately glandular-toothed, apex aristate;

petals yellow to yellow-orange throughout, oblanceolate to narrowly obovate, 5–10 mm;

stamens (3–)4–7 mm;

anthers 0.4–1 mm;

staminodia present or absent;

styles connate nearly to apex, 2–5.7 mm;

stigmas green, capitate.

sepals persistent or deciduous, 5, connate at base, equal or unequal in size, margins scarious, entire, ciliate, or toothed, glandular or not;

petals 5, distinct or coherent at base, attached to filament cup at base, midway, or on or proximal to rim, blue, white, yellow, yellowish orange, orange, or salmon, rarely red or maroon, sometimes with darker bands near base, appendages absent or pouches formed on petal margins at base of claw;

stamens 5;

staminodes 0 or 5, as small deltate projections;

pistil 5-carpellate, ovary 5-locular, or 10-locular by intrusion of false septa;

styles 5, distinct or connate;

stigmas capitate, linear, or clavate, wider than styles.

Fruits

capsules, usually 5-celled and dehiscing into 5 segments, sometimes each cell partially divided by incomplete or nearly complete false septum and dehiscing into 10 segments.

Capsules

ovoid, 3.2–4.5 × 2.5–3.4 mm, relatively thick-walled and with characteristic thickened areas at apex in region of true septa, apex obtuse, dehiscing into 5, 2-seeded segments, segments persistent on plant, false septa complete, proximal part membranaceous, not terminating in loose fringe, distal part cartilaginous, margins ciliate.

Seeds

2–3 × 0.8–1.3 mm.

10, lenticular.

x

= 13, [15, 18].

Linum australe

Linum

Distribution
from FNA
AZ; CO; MT; NM; NV; TX; UT; WY; AB; Mexico
[WildflowerSearch map]
[BONAP county map]
from USDA
Nearly worldwide; temperate and subtropical regions
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

The stems of Linum australe are strongly ridged-sulcate to ribbed, especially distally. The corollas are broadly funnelform; petals are yellow to yellow-orange; stamens and styles are yellow; stigmas are bright to olive green. Staminodia in L. australe are short, deltoid, usually two between each pair of stamens, sometimes one or absent. Linum australe is the only species in its range that is glabrous beyond the base and has connate styles. It differs from L. aristatum, which it overlaps in the southern part of the range, in being much more highly branched and having more slender capsules. C. M. Rogers (1984) noted a compact form found in sunny areas from Wyoming northward that warrants more study.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species ca. 180 (37 in the flora).

C. M. Rogers (1963, 1964, 1968, 1982, 1984) published comprehensive studies of Linum in North America and Central America; he also studied Linum in South America (Rogers and R. Mildner 1976), southern Africa (Rogers 1981), and Madagascar (Rogers 1981b). This treatment draws largely on his work and follows his taxonomic arrangement, which is congruent, at least at the level of section, with the results in J. R. McDill et al. (2009). Species of Linum in the flora have been placed in three sections of the genus, out of a total of five sections worldwide.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Stipular glands present only at proximal nodes; stamens (3–)4–5 mm; styles (2–)2.7–3.3(–4) mm.
var. australe
1. Stipular glands present at nodes throughout plant; stamens 5–7 mm; styles 3.6–5.7 mm.
var. glandulosum
1. Petals yellow, sometimes with maroon at base.
sect. Linopsis
1. Petals red, white, or blue.
→ 2
2. Sepal margins not glandular-toothed; petals usually blue or red to maroon, rarely white.
sect. Linum
2. Sepal margins (at least inner) glandular-toothed, petals white.
sect. Cathartolinum
Source FNA vol. 12, p. 390. FNA vol. 12, p. 373.
Parent taxa Linaceae > Linum > sect. Linopsis Linaceae
Sibling taxa
L. alatum, L. allredii, L. arenicola, L. aristatum, L. berlandieri, L. bienne, L. carteri, L. catharticum, L. compactum, L. elongatum, L. floridanum, L. grandiflorum, L. harperi, L. hudsonioides, L. imbricatum, L. intercursum, L. kingii, L. lewisii, L. lundellii, L. macrocarpum, L. medium, L. neomexicanum, L. perenne, L. pratense, L. puberulum, L. rigidum, L. rupestre, L. schiedeanum, L. striatum, L. subteres, L. sulcatum, L. trigynum, L. usitatissimum, L. vernale, L. virginianum, L. westii
Subordinate taxa
L. australe var. australe, L. australe var. glandulosum
L. sect. Cathartolinum, L. sect. Linopsis, L. sect. Linum
Name authority A. Heller: Bull. Torrey Bot. Club 25: 627. (1898) Linnaeus: Sp. Pl. 1: 277. (1753): Gen Pl. ed. 5, 135. (1754)
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