Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Arabis nuttallii

Nuttall's rockcress
Habit Perennials; (caudex simple or branched, covered with persistent petiolar remains); glabrous or sparsely to densely pubescent, trichomes simple, sometimes subsetiform, (0.3–2 mm), these rarely mixed with fewer, short-stalked, forked ones.
Stems

simple or few to numerous from base (caudex), erect or ascending, unbranched, 0.5–2.5(–3.6) dm, (glabrous throughout or pubescent along proximal 1/2, trichomes simple).
Basal leaves

petiole 0.3–2(–3.5) cm, (glabrous or ciliate);

blade narrowly oblanceolate, spatulate, to obovate, 0.4–2(–3) cm × 3–10(–15) mm, margins entire, (ciliate or not), apex obtuse, surfaces glabrous or sparsely to densely pubescent, trichomes simple, rarely mixed with forked ones.
Cauline leaves

(1 or) 2–5(–7);

blade linear, oblanceolate, oblong, or obovate, 0.5–2.2(–3) cm × 2–8(–12) mm, base not auriculate, margins entire, (sometimes ciliate), apex obtuse, surfaces glabrous or, rarely, sparsely pubescent.
Racemes

simple, (dense or lax).
Flowers

sepals (greenish) oblong, 2.5–3.5 × 1.2–1.5 mm, lateral pair saccate basally, (glabrous);

petals white, oblanceolate to spatulate, (5–)6–8 × 2–4 mm, apex rounded;

filaments 2.5–4 mm;

anthers oblong, 0.6–1 mm.
Fruiting pedicels

ascending to divaricate, (2–)5–20(–30) mm, (glabrous).
Fruits

ascending to suberect, (not appressed to rachis), slightly torulose, sometimes slightly curved, (0.7–)1–2.5(–2.8) cm × 0.8–1.2(–1.5) mm;

valves each with distinct midvein extending full length;

ovules 10–24 per ovary;

style 0.5–1.2(–2) mm, (slender).
Seeds

not winged, broadly ovate, 0.6–1.2(–1.5) × 0.5–1 mm.
2n

= 32.

Arabis nuttallii
Phenology Flowering Apr–Aug.
Habitat Alpine and subalpine meadows and slopes, open woods, steep slopes and cliffs, mossy mats, dry or moist slopes and hillsides, ridge crests
Elevation 500-3200 m [1600-10500 ft]
Distribution
from FNA
ID; MT; UT; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

Arabis nuttallii, the second most widespread native North American species of the genus, is variable in density of indumentum, types of trichomes, plant height, pedicel length, fruit width, leaf shape, flowering and fruiting time, and elevation. As indicated by R. C. Rollins (1941, 1993), the variation seems to be sporadic and does not correlate with clear-cut entities and, therefore, the species cannot be subdivided meaningfully.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 263. Treatment author: Ihsan A. Al-Shehbaz.
Parent taxa Brassicaceae > tribe Arabideae > Arabis
Sibling taxa
A. aculeolata, A. alpina, A. blepharophylla, A. caucasica, A. crucisetosa, A. eschscholtziana, A. furcata, A. georgiana, A. mcdonaldiana, A. modesta, A. olympica, A. oregana, A. patens, A. pycnocarpa
Synonyms Erysimum nuttallii, A. bridgeri, A. macella
Name authority (Kuntze) B. L. Robinson: in A. Gray et al., Syn. Fl. N. Amer. 1(1,1): 160. (1895)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Boraginaceae and Polemoniaceae.)

The species comparison tool is brought to you by:
Northwest Wildflowers