Species: Atriplex powellii S. Wats.

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Atriplex powellii S. Wats.

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TAXONOMY

Family:

Chenopodiaceae

Genus:

Atriplex

Species Synonyms:

none

Common Names:

Powell’s saltbush
Powell’s orache
Powell’s saltweed
Powell’s silverscale

DISTRIBUTION

Canada:

southern Alberta – southwestern Saskatchewan

Saskatchewan:

southwestern Saskatchewan; Cabri Lake - Lower Frenchman River Valley - Wood Mountain

Ecoregion:

Mixed Grassland

HABITAT

Saskatchewan:

dry, subsaline clay flats

Associated Species:

Atriplex argentea, Chenopodium album, Chenopodium leptophyllum, Grindelia squarrosa, Machaeranthera canescens var. canescens, Polygonum aviculare, Suaeda calceoliformis

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

G4G5 N2 S1

Saskatchewan Species at
Risk Status:

Endangered

COSEWIC Status:

None

Atriplex powellii is endangered in Saskatchewan because it is regionally restricted in the province. A. powellii is usually locally numerous, but within limited areas. Possible threats to this species include human development and fragile habitat.

SPECIES DESCRIPTION

* kranz-type venation: appears as a dark green net pattern when leaf surface is lightly scraped with a sharp blade under 10X magnification

Height:

5 – 100 cm, may be as wide as tall with branching

Roots:

taproot

Stems:

annual, herbaceous, erect, branched at base, curved upwards, shallowly ridged, straw-coloured

Leaves:

alternate, lowest leaves may be opposite; lower leaves slender, short-petioled; upper leaves sessile, 1 – 3 cm long, almost as wide as long, ovate, base rounded or slightly cuneate, conspicuously 3-nerved, kranz-type venation; silvery-gray farinose

Inflorescence:

monoecious

Flowers:

staminate perianth 5-parted, stamens 5; pistillate flowers sessile, bracteoles 2, 3 – 4 mm long, 3 – 4 mm wide, oblong, thick, appendaged, united to tip, irregularly toothed

Fruits:

seeds to 1.6 mm long, flat, light brown or yellowish

ATRIPLEX KEY FOR SPECIES FOUND IN SASKATCHEWAN

* kranz-type venation: appears as a dark green net pattern when leaf surface is lightly scraped with a sharp blade under 10X magnification

1 Plants perennial, woody at least in part; leaves with kranz-type venation	2
1 Plants annual, herbaceous throughout; leaves with kranz-type or other venation	3

2 Plants woody at base; fruiting bracteoles not winged lengthwise	A. gardneri
2 Plants woody throughout; fruiting bracteoles prominently 4-winged lengthwise	A. gardneri var. aptera

3 All leaves sessile	4
3 At least some leaves petiolate	6

4 At least some parts of plant usually farinose, scurfy, or otherwise pubescent; leaf base cuneate, truncate or cordate; pistillate flowers in glomerules in terminal and axillary spikes	A. truncata
4 Plants glabrous or nearly so; leaves tapering to base; pistillate flowers solitary or clustered in leaf axils	5

5 Leaves and stems green and glabrous	A. dioica
5 Leaves glaucous, sparingly farinose when young; stems reddish	A. suckleyi

6 Plants with kranz-type* venation	7
6 Plants with normal dicot venation	9

7 Bracteoles obovate, 4 – 8 mm long, margin dentate, usually bony and hard	A. argentea var. argentea
7 Bracteoles cuneate or oblong, 2 – 3.5 mm long, not dentate-margined or hard and bony	8

8 Leaves subsessile, not conspicuously nerved; bracteoles cuneate, 2 – 3 mm long	A. truncata
8 Leaves with slender petioles, conspicuously 3-nerved, bracteoles oblong, 3 – 4 mm long	A. powellii

9 Herbage green; bracteoles orbicular, entire	A. hortensis
9 Herbage scurfy or mealy; bracteoles not orbicular, toothed	10

10 Leaves hastate; seeds circular	A. prostrata
10 Leaves ovate to lanceolate or linear; seeds elliptic	A. patula