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spreading rockcress

Habit Biennials or, rarely, perennials; (short-lived, with caudex); usually densely hirsute (at least basally), trichomes simple (to 1 mm), sometimes mixed with stalked, forked ones. Annuals, biennials, or perennials [subshrubs]; eglandular.
Stems

simple or several from base (rosette), erect, often branched distally, (1.8–)2.5–4.5(–5.5) dm, (hirsute at least basally).

Basal leaves

petiole (0.7–)2–5 cm;

blade usually ovate to oblanceolate, rarely cordate, (0.8–)1.5–3 cm × 5–17 mm, margins dentate or serrate, surfaces sparsely to densely pubescent, trichomes simple or forked.

Cauline leaves

(5–)8–20(–27), (overlapping or not);

blade ovate to oblong or lanceolate, (2–)3–7.5(–9) cm × (10–)13–25(–35) mm, base amplexicaul, margins usually dentate or serrate, sometimes entire, surfaces hirsute.

petiolate or sessile;

blade base auriculate or not, margins entire or dentate.

Trichomes

stalked or sessile, usually stellate, dendritic, cruciform, or forked, sometimes mixed with simple ones, rarely malpighiaceous.

Racemes

branched.

usually ebracteate, often elongated in fruit.

Flowers

sepals oblong, 2.5–4.5 × 1–1.5 mm, lateral pair slightly saccate basally;

petals white, spatulate, (5–)6–9 × 2–3.5 mm, apex obtuse;

filaments 3–5 mm;

anthers oblong, 0.8–1.2 mm.

actinomorphic;

sepals erect, ascending, or spreading, lateral pair seldom saccate basally;

petals white, yellow, orange, pink, or purple, claw usually present, usually distinct;

filaments unappendaged, not winged;

pollen 3-colpate.

Fruiting pedicels

ascending to divaricate-ascending, (7–)10–20(–24) mm, (glabrous or sparsely pubescent).

Fruits

divaricate to erect-ascending, (not appressed to rachis), torulose, 2.2–4.6 cm × 0.8–1.2mm;

valves each with prominent midvein extending to middle or full length;

ovules 16–28 per ovary;

style 0.5–2 mm, (slender).

silicles or siliques, usually dehiscent, very rarely indehiscent, unsegmented, latiseptate or terete;

ovules 2–70(–88)[–110+] per ovary;

style usually distinct, sometimes obsolete;

stigma usually entire, rarely 2-lobed.

Seeds

narrowly winged distally, oblong, 1–1.6 × 0.6–0.8 mm;

wing 0.05–0.1 mm.

biseriate or uniseriate [rarely aseriate];

cotyledons accumbent.

Arabis patens

Brassicaceae tribe Arabideae

Phenology Flowering Apr–May.
Habitat Rocky wooded slopes, shady stream banks, limestone ledges and bluffs
Elevation 0-500 m (0-1600 ft)
Distribution
from FNA
DC; IN; KY; MD; NC; OH; PA; TN; VA; WV
[WildflowerSearch map]
[BONAP county map]
North America; Mexico; South America; Europe; Asia; n Africa
Discussion

Genera 8, species ca. 460 (4 genera, 139 species in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 7, p. 262. FNA vol. 7, p. 256.
Parent taxa Brassicaceae > tribe Arabideae > Arabis Brassicaceae
Sibling taxa
A. aculeolata, A. alpina, A. blepharophylla, A. caucasica, A. crucisetosa, A. eschscholtziana, A. furcata, A. georgiana, A. mcdonaldiana, A. modesta, A. nuttallii, A. olympica, A. oregana, A. pycnocarpa
Subordinate taxa
Synonyms Boechera patens
Name authority Sullivant: Amer. J. Sci. Arts 42: 49. (1842) de Candolle: Mém. Mus. Hist. Nat. 7: 229. (1821)
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