Jepson eFlora: Taxon page
Key to families | Table of families and genera
Previous taxon Index to accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Next taxon
Arabis mcdonaldiana
MCDONALD'S ROCKCRESS

Higher Taxonomy
Family: Brassicaceae (Cruciferae)View DescriptionDichotomous Key

Common Name: MUSTARD FAMILY
Habit: Annual to shrub; sap pungent, watery. Leaf: generally simple, alternate; generally both basal, cauline; stipules 0. Inflorescence: generally raceme, generally not bracted. Flower: bisexual, generally radial; sepals 4, generally free; petals (0)4, forming a cross, generally white or yellow to purple; stamens generally 6 (2 or 4), 4 long, 2 short (3 pairs of unequal length); ovary 1, superior, generally 2-chambered with septum connecting 2 parietal placentas; style 1, stigma entire or 2-lobed. Fruit: capsule, generally 2-valved, "silique" (length >= 3 × width) or "silicle" (length < 3 × width), dehiscent by 2 valves or indehiscent, cylindric or flat parallel or perpendicular to septum, segmented or not. Seed: 1--many, in 1 or 2 rows per chamber, winged or wingless; embryo strongly curved.
Genera In Family: +- 330 genera, 3780 species: worldwide, especially temperate. Note: Highest diversity in Mediterranean area, mountains of southwestern Asia, adjacent central Asia, western North America; some Brassica species are oil or vegetable crops; Arabidopsis thaliana used in experimental molecular biology; many species are ornamentals, weeds. Aurinia saxatilis (L.) Desvaux in cultivation only. Aubrieta occasional waif in central NCoR, Carrichtera annua (L.) DC. in SCo, Iberis sempervirens L., Iberis umbellata L. in PR, Teesdalia coronopifolia (Bergeret) Thell., Teesdalia nudicaulis (L.) W.T. Aiton in southern NCoRO, CCo. Cardaria, Coronopus moved to Lepidium; Caulostramina to Hesperidanthus; Guillenia to Caulanthus; Heterodraba to Athysanus; California taxa of Lesquerella to Physaria; Malcolmia africana to Strigosella.
eFlora Treatment Author: Ihsan A. Al-Shehbaz, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: ArabisView DescriptionDichotomous Key

Common Name: ROCKCRESS
Habit: Annual, biennial, perennial herb; base not woody; hairs simple, forked, or stellate; caudex branched or not. Stem: branched or not, leafy. Leaf: basal rosetted, petioled, entire or dentate; cauline sessile, entire or dentate, base lobed or not. Flower: sepals erect or ascending, base of lateral pair sac-like or not; petals spoon-shaped to oblong, oblanceolate, or obovate, white to pink or deep purple. Fruit: silique, erect to spreading, linear, dehiscent, unsegmented, straight, flat parallel to septum, glabrous. Seed: 12--110, 1 row per chamber, flat, winged or margined.
Species In Genus: < 70 species: temperate North America, Eurasia, northern Africa. Etymology: (Latin: of Arabia) Note: Most species of Arabis in TJM (1993) moved to Boechera; Arabis glabra to Turritis. California record of Arabis aculeolata Greene not confirmed.

Arabis mcdonaldiana Eastw.
NATIVE
Habit: Perennial herb; caudex branched. Stem: few to many, simple, (0.6)1.5--3(4) dm, slender, glabrous. Leaf: basal 1--4(5.5) cm, entire, wavy-margined to few-dentate, glabrous or teeth bristle-tipped; cauline (2)3--5(6), well spaced, oblong, entire, base tapered, not basally lobed. Flower: sepals 4--8 mm; petals 8--16 mm, 2--5 mm wide, spoon-shaped, purple. Fruit: erect to ascending, 2--4 cm, 1.5--2 mm wide, flat, glabrous; style 0.3--1.5 mm; pedicel ascending, 3--10(13) mm, glabrous. Seed: 20--34, oblong; wing 0.1--0.2 mm wide, at 1 end or 0. Chromosomes: 2n=16.
Ecology: Deep +- red soils, steep slopes, dry ridges, serpentine areas; Elevation: 200--1800 m. Bioregional Distribution: NCoRO. Flowering Time: May--Jun
Synonyms: Arabis blepharophylla Hook. & Arn. var. macdonaldiana (Eastw.) Jeps.; Arabis serpentinicola Rollins; Arabis macdonaldiana Eastw., orth. var.
eFlora Treatment Author: Ihsan A. Al-Shehbaz
Jepson Online Interchange
Listed on CNPS Rare Plant Inventory

Previous taxon: Arabis eschscholtziana
Next taxon: Arabis modesta

Name Search

Contact/Feedback

Citation for this treatment: Ihsan A. Al-Shehbaz 2016. Arabis mcdonaldiana, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=13763, accessed on August 27, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on August 27, 2016.


Geographic subdivisions for Arabis mcdonaldiana:
NCoRO.
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
READ ABOUT YELLOW FLAGS
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.