Arabidopsis arenosa subsp. arenosa

Treatment appears in FNA Volume 7. Treatment on page 448. Mentioned on page 449.

Biennials or perennials; (caudex short); glabrous or pubescent, trichomes simple with or stellate or forked ones. Stems often several from base, erect or decumbent, usually branched distally, (0.5–) 1.5–6 (–8) dm, pubescent basally with simple, 1-forked, or 3-rayed stellate trichomes, sparsely pubescent or glabrous apically. Basal leaves: petiole (0.6–) 1.5–3.5 (–5) cm; blade oblanceolate, (0.6–) 2–6 (–9) cm × (3–) 10–20 (–30) mm, margins pinnatisect or pinnatipartite, with 3–10 lobes on each side, apex obtuse to acute, surfaces sparsely to densely pubescent. Cauline leaves shortly petiolate or sessile; blade oblanceolate, (0.4–) 1.5–5 (–6.5) cm × (2–) 8–20 (–30) mm (gradually smaller distally), margins usually pinnatifid to coarsely toothed, rarely subentire. Fruiting pedicels divaricate or ascending, (4–) 5–12 (–15) mm. Flowers: sepals (1.7–) 2–3 mm, lateral pair subsaccate basally, (glabrous or pubescent); petals white or lavender, spatulate or obovate, (5–) 6–8 (–9) × (2.5–) 3–5 mm, (claw to 2 mm, with a tooth on each side); filaments 2.5–4.5 mm. Fruits torulose, flattened, (1.5–) 2–4 (–4.8) cm × 0.8–1.2 mm; valves each with distinct midvein; style (0.2–) 0.5–0.9 (–1.3) mm. Seeds light-brown, (flattened), ovoid, 0.8–1 mm; cotyledons accumbent. 2n = 16, 32.


Phenology: Flowering Jul.
Habitat: Above fjords
Elevation: 0 m

Discussion

This is the first record of subsp. arenosa from North America. It is based on M. P. Porsild s.n. (MO) collected from western Greenland, 28 July 1935. It is not known if the occurrence in Greenland represents an introduction or the westernmost extent of its native range.

Selected References

None.

Lower Taxa

None.

"elongated" is not a number."thick" is not a number."dm" is not declared as a valid unit of measurement for this property.

ovate +  and oblong +
Obtuse (?) +  and Acute (?) +
Ihsan A. Al-Shehbaz +
(Linnaeus) Lawalrée +
Sisymbrium arenosum +
appendaged +  and unappendaged +
5 cm50 mm <br />0.05 m <br /> (6.5 cm65 mm <br />0.065 m <br />) +
2 cm20 mm <br />0.02 m <br /> (3 cm30 mm <br />0.03 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (5 cm50 mm <br />0.05 m <br />) +
lyrate +, lobed +, toothed +  and entire +
oblanceolate;oblanceolate +
much smaller +  and reduced +
8mm;20mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
sessile +  and petiolate +
well-developed +
distinct +
differentiated +
emarginate +  and entire +
Greenland +  and Europe +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
actinomorphic +
2-valved +  and capsular +
4 cm40 mm <br />0.04 m <br /> (4.8 cm48 mm <br />0.048 m <br />) +
flattened +  and torulose +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
latiseptate +  and unsegmented +
indehiscent +  and dehiscent +
angustiseptate +  and terete +
latiseptate +, subsessile +  and stipitate +
terete +  and torulose +
Above fjords +
subsessile +, sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
pinnatipartite +  and pinnatisect +
1.2 cm12 mm <br />0.012 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
subentire;usually pinnatifid;coarsely toothed +
obscure +  and prominent +
1-3-forked +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
0.8 cm8 mm <br />0.008 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
rudimentary +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
3.5 cm35 mm <br />0.035 m <br /> (5 cm50 mm <br />0.05 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
Flowering Jul. +
trinucleate +  and 3(-11)-colpate +
Bull. Soc. Roy. Bot. Belgique +
not elongated +
reflexed +  and ascending +
slender +
not +  and mucilaginous +
margined +  and not winged +
uniseriate +  and biseriate +
not +  and mucilaginous +
0.8mm +  and 1mm +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
persistent +  and caducous +
distinct +
ascending +  and erect +
subsaccate +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
reduced +
latiseptate +, schizocarpic +, samaroid +  and lomentaceous +
indehiscent +  and dehiscent +
angustiseptate +, flat +, angled +, terete +, torulose +, not +, segmented +  and nutletlike +
tetradynamous +
procumbent +  and decumbent +
decumbent +  and erect +
2-lobed +, entire +, conical +  and capitate +
subsessile +, sessile +  and petiolate +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
persistent +
distinct +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.09 cm0.9 mm <br />9.0e-4 m <br />) +
Cruciferae +
Arabidopsis arenosa subsp. arenosa +
Arabidopsis arenosa +
subspecies +
1-forked +, forked +  and stellate +
pubescent +  and glabrous +
anastomosing +
perennial +  and biennial +
pubescent +  and glabrous +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +