Arabis mcdonaldiana

Eastwood

Bull. Torrey Bot. Club 30: 488, unnumb. fig. (p. 489). 1903.

EndemicConservation concern
Synonyms: Arabis blepharophylla var. mcdonaldiana (Eastwood) Jepson Arabis serpentinicola Rollins
Treatment appears in FNA Volume 7. Treatment on page 265. Mentioned on page 258, 264.

Perennials; (caudex simple or branched, covered with persistent petiolar remains); usually glabrous, rarely sparsely pubescent, trichomes simple, (to 0.5 mm), not bulbous-based. Stems simple or few from base (caudex), erect, unbranched, (0.6–) 1.5–3 (–4) dm, (glabrous). Basal leaves: petiole 0.3–1.5 cm; blade oblanceolate to obovate, (0.5–) 1–3 (–4) cm × (2–) 3–6 (–10) mm, margins entire, repand, or obtusely dentate, apex obtuse, surfaces sometimes with individual trichomes terminating some or all leaf teeth. Cauline leaves (2 or) 3–5 (or 6); blade oblong, 0.3–1 (–1.2) cm × 1–3 mm, base not auriculate, margins entire or repand, apex obtuse, surfaces glabrous. Racemes simple, (dense). Fruiting pedicels ascending to suberect, 3–10 (–13) mm. Flowers: sepals (purple), oblong, 4–8 × 1.5–2.5 mm, lateral pair saccate basally; petals purple, spatulate, 8–16 × 2–5 mm, apex obtuse; filaments 4–8 mm; anthers oblong, 1.5–2 mm. Fruits ascending to suberect, not torulose, sometimes slightly curved, 2–4 cm × 1.5–2 mm; valves each with prominent midvein extending full length; ovules 20–34 per ovary; style 0.3–1.5 mm. Seeds narrowly winged distally or, rarely, not winged, oblong, 1.5–2.2 × 1–1.3 mm, wing 0.1–0.2 mm wide.


Phenology: Flowering May–Jun.
Habitat: Serpentine scrap and slopes, red serpentinized soil
Elevation: 200-1800 m

Discussion

Of conservation concern.

Arabis mcdonaldiana is known in California from Del Norte, Mendocino, and Siskiyou counties, and in Oregon from Curry and Jackson counties. It is in the Center for Plant Conservation’s National Collection of Endangered Plants.

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

... more about "Arabis mcdonaldiana"
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Ihsan A. Al-Shehbaz +
Eastwood +
sessile +  and petiolate +
not auriculate +
appendaged +  and unappendaged +
1 cm10 mm <br />0.01 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (1 cm10 mm <br />0.01 m <br />) +
not +  and auriculate +
0.3 cm3 mm <br />0.003 m <br /> (1 cm10 mm <br />0.01 m <br />) +
lyrate-pinnatifid +, dentate to denticulate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblong;oblanceolate;obovate +
much smaller +  and reduced +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
distinct +
differentiated +
emarginate +  and entire +
Calif. +  and Oreg. +
200-1800 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
0.4 cm4 mm <br />0.004 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
actinomorphic +
0.4 cm4 mm <br />0.004 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
latiseptate +  and unsegmented +
indehiscent +  and dehiscent +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
ascending +  and suberect +
not torulose +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
latiseptate +, stipitate +  and sessile +
flattened +  and torulose +
Serpentine scrap and slopes, red serpentinized soil +
annular +  and semiannular +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
dentate +  and entire +
repand;entire;dentate;repand;dentate;repand;entire +
forked +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
purple +, pink +  and white +
8mm;16mm +
rudimentary +
spatulate +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
Flowering May–Jun. +
trinucleate +  and 3(-11)-colpate +
Bull. Torrey Bot. Club +
1 cm10 mm <br />0.01 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
ascending +  and suberect +
slender +
0.3 cm3 mm <br />0.003 m <br /> (1 cm10 mm <br />0.01 m <br />) +
mucilaginous +
uniseriate +  and biseriate +
not +  and mucilaginous +
white +, black +, brown +  and yellow +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
not basally +  and saccate +
persistent +  and caducous +
distinct +
ascending +  and erect +
oblong +  and ovate +
reduced +
latiseptate +  and unsegmented +
indehiscent +  and dehiscent +
latiseptate +  and unsegmented +
indehiscent +  and dehiscent +
Endemic +  and Conservation concern +
tetradynamous +
unbranched +  and simple +
procumbent +  and decumbent +
subsessile +, sessile +  and petiolate +
persistent +
distinct +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
Arabis blepharophylla var. mcdonaldiana +  and Arabis serpentinicola +
Arabis mcdonaldiana +
species +
not bulbous-based +  and simple +
forked +  and cruciform +
coiled +, 1-7-veined +  and veined +
anastomosing +
pubescent +  and glabrous +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
0.1mm;0.2mm +