Species: Arabis arenicola (Richards. ex Hook.) Gelert

comments | credits | copyright

Back to: Plants at Risk in Saskatchewan

Arabis arenicola (Richards. ex Hook.) Gelert

Species Image Gallery
(opens in a new window)

TAXONOMY

Family:

Brassicaceae

Genus:

Arabis

Species Synonyms:

none

Common Names:

sand rockcress
arctic rock-cress

DISTRIBUTION

Canada:

Mackenzie District (Northwest Territories) - Keewatin District, Nunavut - Baffin Island, south to northwestern Saskatchewan, northern Manitoba - northern Ontario

Saskatchewan:

northwestern Saskatchewan; Lake Athabasca

Ecoregion:

Athabasca Plain, Tazin Lake Upland

HABITAT

Saskatchewan:

sand dunes and gravel flats

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

G5 S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Arabis arenicola is endangered in Saskatchewan because it is highly regionally restricted and most local populations are small.

SPECIES DESCRIPTION

Height:

10 – 30 cm

Roots:

taproot long, slender

Stems:

perennial, erect, hirsute below, otherwise glabrous

Leaves:

basal and cauline; basal rosette, leaves many, 1 – 7 cm long, 4 – 7 mm wide, spatulate to oblanceolate, purple in age, glabrous to hirsute, margin entire to shallowly dentate, with up to three pairs of teeth, slightly fleshy; cauline leaves few, alternate, sessile, oblong, cuneate at base, margin less toothed than basal leaves

Inflorescence:

raceme terminal

Flowers:

small; calyx < 3 mm long; corolla to 5 mm long, white or pinkish

Fruits:

silique 1 – 3 cm long, 1 – 2 mm wide, ascending to spreading, glabrous; seeds < 1 mm broad, in two rows, wingless; replum persistent after seed dispersal

ARABIS KEY IN SASKATCHEWAN

1 Pedicels and fruits strongly deflexed at maturity	2
1 Pedicels and fruits erect, ascending or spreading at maturity	4

2 Basal leaves densely pubescent with coarse, branching hairs; pedicels gently curved downwards, pods pendulous	A. holboellii var. pinetorum
2 Basal leaves finely pubescent; pedicels geniculate near base, straight or at least not uniformly curved, pods reflexed but not pendulous	3

3 Lower stem hirsute, with long, spreading, simple and forked hairs; rosette leaves < 5 cm long, cauline leaves < 2.5 cm long and 5 mm broad; pods to 6 cm long, 1.5 mm broad	A. holboellii var. collinsii
3 Lower stem finely hoary-stellate; rosette leaves to 8 cm long, cauline leaves to 4 cm long and 9 mm broad; pods to 8 cm long and 2.5 mm broad	A. holboellii var. retrofracta

4 Pedicels erect or nearly so, closely appressed to stem	5
4 Pedicels spreading or ascending, but not erect and appressed to the stem	7

5 Fruits terete or nearly so	A. glabra
5 Fruits flat	6

6 Stem hairy below; silique 3 – 5 cm long, 0.7 – 1.0 mm wide; seeds uniseriate in each locule	A. hirsuta var. pycnocarpa
6 Stem commonly glabrous; silique 5 – 9 cm long, 1.5 – 2.3 mm wide; seeds biseriate in each locule	A. drummondii

7 Cauline leaves auriculate	A. divaricarpa
7 Cauline leaves not auriculate	8

8 Basal leaves lyrately lobed; petals to 8 mm long; pods to 4.5 cm, < 1.5 mm broad; seeds uniseriate	A. lyrata
8 Basal leaves entire to dentate; petals to 5 mm long; pods to 3 cm long, about 2 mm broad; seeds biseriate	A. arenicola