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Boechera johnstonii

JOHNSTON'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: BoecheraView DescriptionDichotomous Key


Common Name: ROCKCRESS
Habit: Perennial herb (biennial); caudex simple or branched, persistent leaf bases generally absent; rosetted or not; rosette at ground surface or elevated on woody base; hairs simple or 2--14-rayed, stalked or sessile. Stem: simple or branched, leafy. Leaf: basal petioled, simple, generally entire or dentate, generally hairy; cauline sessile, base generally lobed, entire or dentate. Inflorescence: generally elongated. Flower: sepals bases generally not sac-like; petals generally white, lavender, or purple, claw present or 0; pollen ellipsoid in sexual pls, spheric in plants with asexual seeds. Fruit: silique, dehiscent, generally linear, edges generally parallel, unsegmented, flat parallel to septum; stigma entire or 2-lobed. Seed: in 1 or 2 rows, winged or not.
Etymology: (T.W. Boecher, Danish cytogeneticist, 1909--1983) Note: Some species with both fertile & sterile stems. Previously included in Arabis, but the 2 genera in different tribes. Boechera horizontalis (Greene) Windham & Al-Shehbaz [Arabis suffrutescens S. Watson var. horizontalis (Greene) Rollins] not in California.
Unabridged Note: Hybrids with spheric pollen and morphological intermediacy generally more common than sexual diploids (with ellipsoid pollen).
eFlora Treatment Author: Michael D. Windham & Ihsan A. Al-Shehbaz
Reference: Windham & Al-Shehbaz 2006--2007 Harvard Pap Bot 11:61--88, 11:257--274, 12:235--257
Unabridged Reference: Al-Shehbaz 2003 Novon 13:381--391
Boechera johnstonii (Munz) Al-Shehbaz
NATIVE
Habit: Caudex woody. Stem: generally 1 per caudex branch, from center of basal rosette at +- ground surface; 0.5--2 dm, proximally with short-stalked, 4--10-rayed hairs 0.07--0.15 mm. Leaf: basal 1.5--4 mm wide, entire; hairs short-stalked, 6--14-rayed 0.07--0.15 mm; cauline 4--10, distal hairy, basal lobes 0. Inflorescence: 10--18-flowered, not 1-sided in fruit; fruit pedicel spreading-ascending, straight, 5--14 mm, hairs appressed, branched. Flower: sepals hairy; petals 9--14 mm, 2--4 mm wide, purple; pollen ellipsoid. Fruit: spreading-ascending, not appressed, 4--6 cm, 2.5--4 mm wide, glabrous; style 0.7--2 mm; ovules 26--34. Seed: in 1 row, 1.9--2.7 mm; wing 0.3--0.7 mm wide.
Ecology: Rocky areas, gravelly soil, in chaparral, grassland, open oak/pine woodland; Elevation: 1300--1700 m. Bioregional Distribution: PR (Cuyamaca Mtns, SnJt). Flowering Time: Feb--Mar
Synonyms: Arabis johnstonii Munz; Arabis hirshbergiae S. Boyd; Boechera hirshbergiae (S. Boyd) Al-Shehbaz Listed in CNPS Inventory
Jepson eFlora Author: Michael D. Windham & Ihsan A. Al-Shehbaz
Reference: Windham & Al-Shehbaz 2006--2007 Harvard Pap Bot 11:61--88, 11:257--274, 12:235--257
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Listed on CNPS Rare Plant Inventory

Previous taxon: Boechera inyoensis
Next taxon: Boechera koehleri


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Citation for this treatment: Michael D. Windham & Ihsan A. Al-Shehbaz 2012, Boechera johnstonii, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=85470, accessed on December 03, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on December 03, 2024.

Boechera johnstonii
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©2009 Thomas Stoughton
Boechera johnstonii
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©2009 Thomas Stoughton
Boechera johnstonii
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©1999 John Game
Boechera johnstonii
click for image enlargement
©1999 John Game
Boechera johnstonii
click for image enlargement
©1999 John Game

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Geographic subdivisions for Boechera johnstonii:
PR (Cuyamaca Mtns, SnJt).
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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 occurrence).






 

Data provided by the participants of the  Consortium of California Herbaria.

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All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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CCH collections by month Flowering-Fruiting Monthly Counts

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).