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southern flax

Bicknell's yellow flax, sandplain flax, sandplain yellow flax

Habit Herbs, annual, 10–50 cm, puberulent near base, otherwise glabrous. Herbs or subshrubs, perennial, 20–92 cm, glabrous.
Stems

stiffly ascending-spreading, few to many-branched.

erect, unbranched proximal to inflorescence or few-branched at base.

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.

proximalmost opposite, distalmost alternate, sometimes opposite nearly to inflorescence, erect to ascending;

stipular glands absent;

blade narrowly elliptic to oblanceolate, 8–27 × 1.2–5.6 mm, margins entire, not ciliate, apex acute;

internal venation shown by transmitted light.

Inflorescences

racemes.

panicles.

Pedicels

3–15 mm.

0–5 mm.

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, lanceolate, 2–3 mm, margins not scarious, entire, or inner and rarely outer sparsely glandular-toothed, apex sharp-pointed;

petals yellow, obovate, 4–7 mm;

stamens 3 mm;

anthers 0.5–1 mm;

staminodia absent;

styles distinct, 1.5–2.5 mm;

stigmas capitate.

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.

turbinate, 2–3 × 2–2.3 mm, apex acute or obtuse, dehiscing freely into 10, sharp-pointed 1-seeded segments, segments persistent on plant, false septa incomplete, proximal margins sparsely but conspicuously ciliate.

Seeds

2–3 × 0.8–1.3 mm.

1.3–1.8 × 0.6–0.9 mm.

2n

= 36.

Linum australe

Linum intercursum

Phenology Flowering Jun–Oct.
Habitat sometimes in alternately wet and dry, hardpan soils.
Elevation 0–800 m. (0–2600 ft.)
Distribution
from FNA
AZ; CO; MT; NM; NV; TX; UT; WY; AB; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; CT; DC; DE; GA; IN; MA; MD; NC; NJ; NY; PA; RI; SC; TN; VA
[WildflowerSearch map]
[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.)

Linum intercursum is sometimes confused with L. floridanum, from which it differs by its pointed capsule and broader leaves. All parts of the flower of L. intercursum are yellow, and the corolla is nearly rotate.

(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
Source FNA vol. 12, p. 390. FNA vol. 12, p. 382.
Parent taxa Linaceae > Linum > sect. Linopsis Linaceae > Linum > sect. Linopsis
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
L. alatum, L. allredii, L. arenicola, L. aristatum, L. australe, L. berlandieri, L. bienne, L. carteri, L. catharticum, L. compactum, L. elongatum, L. floridanum, L. grandiflorum, L. harperi, L. hudsonioides, L. imbricatum, 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
Synonyms Cathartolinum intercursum
Name authority A. Heller: Bull. Torrey Bot. Club 25: 627. (1898) E. P. Bicknell: Bull. Torrey Bot. Club 39: 418. (1912)
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