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rock flax

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

Habit Herbs, perennial, 20–75 cm, glabrous or rarely sparsely hairy proximally. Herbs or subshrubs, perennial, 20–92 cm, glabrous.
Stems

erect, branched at base and in inflorescence.

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

Leaves

opposite near base or alternate throughout, appressed-ascending;

stipular glands present;

blade linear to linear-lanceolate, 8–20 × 0.5–2.1 mm, margins entire or with scattered minute marginal glands, not ciliate, apex acute; 1-nerved.

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

panicles, with ascending to spreading branches.

panicles.

Pedicels

0–3 mm.

0–5 mm.

Flowers

sepals persistent, lanceolate to ovate, 2.5–5 mm, margins of inner sepals narrowly scarious, conspicuously glandular-toothed, apex acute or acuminate;

petals lemon yellow, oblanceolate or narrowly obcordate, 7–11 mm;

stamens 2–8 mm;

anthers 0.5–1 mm;

staminodia present;

styles distinct, 3–6.5 mm;

stigmas 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, 2–3 × 2–2.5 mm, apex sharp-pointed, dehiscing readily into 10, 1-seeded segments, segments falling freely, false septa incomplete, false and true septa 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

1.2–1.9 × 0.7–1.1 mm.

1.3–1.8 × 0.6–0.9 mm.

2n

= 36.

= 36.

Linum rupestre

Linum intercursum

Phenology Flowering Apr–Aug. Flowering Jun–Oct.
Habitat Sandy soils, rocky slopes and ledges, often on limestone. sometimes in alternately wet and dry, hardpan soils.
Elevation 150–1500 m. (500–4900 ft.) 0–800 m. (0–2600 ft.)
Distribution
from FNA
NM; TX; Mexico (Chihuahua, Coahuila, Durango, Nuevo León); Central America (Guatemala)
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from FNA
AL; CT; DC; DE; GA; IN; MA; MD; NC; NJ; NY; PA; RI; SC; TN; VA
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[BONAP county map]
Discussion

Linum rupestre has narrowly funnelform corollas and yellow stamens and styles. The anthers and stigmas are held closely adjacent at the mouth of the corolla tube, below the broad, spreading limbs. The species occurs from southeastern New Mexico and central Texas to Guatemala. It often grows with L. schiedeanum in Texas and Mexico.

(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.)

Source FNA vol. 12, p. 381. 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. australe, 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. 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
Synonyms Cathartolinum intercursum
Name authority Engelmann ex A. Gray: Boston J. Nat. Hist. 6: 232. (1850) E. P. Bicknell: Bull. Torrey Bot. Club 39: 418. (1912)
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