Species: Canadanthus modestus (Lindl.) Nesom

comments | credits | copyright

Back to: Plants at Risk in Saskatchewan

Canadanthus modestus (Lindl.) Nesom

Species Image Gallery
(opens in a new window)

TAXONOMY

Family:

Asteraceae or Compositae

Genus:

Canadanthus

Species Synonyms:

Weberaster modestus (Lindl.) A. & D. Löve
Aster unalaskensis var. major Hook.
Aster major (Hook.) Porter
Aster modestus Lindl.

Common Names:

large northern aster
giant mountain aster

DISTRIBUTION

Canada:

British Columbia – southern Yukon Territory – Alberta, central Saskatchewan – Ontario

Saskatchewan:

central Saskatchewan; Makwa Lake – Waterhen and Upper Beaver River – southern Lac Ile-a-la-Crosse – Macdowall

Ecoregion:

Boreal Transition, Mid-Boreal Upland

HABITAT

Saskatchewan:

moist, well-drained woods and clearings and roadsides

Associated species:

awned sedge, Baltic rush, fireweed, fringed brome, golden sedge, sage willow, Siberian yarrow, tall bluebells, tamarack, water horehound

RARITY STATUS

Provincial Status According
to Harms (2003):

Threatened

Nature Conservancy Status:

G5 S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Large northern aster is threatened because it is regionally restricted in Saskatchewan. Local populations are usually large but are limited to localized areas. No immediate threats are known for this species.

SPECIES DESCRIPTION

Height:

30 – 75 cm tall

Roots:

rhizomes fibrous, creeping

Stem:

perennial, branched upwards, very leafy, often purplish, especially at the base, densely long-hairy to hairless, more so at base

Leaves:

on the stem, alternate, sessile to clasping, 4 – 8 cm long, 1 – 2 cm wide, lance-shaped, broadest below the middle, base more or less with ear-like lobes, apex tapered, hairless or hairy, margin entire to distantly saw-toothed

Inflorescence:

heads several, to 1.5 cm broad, cluster loose and round-topped; stalks long, leafy-bracted, glandular; bracts in 1 – 2 subequal series, 7 – 11 mm high, tapered, purple to brown to green with brown midvein, glandular

Flowers:

ray and disc flowers; ray flowers 35 – 50, to 8 mm long, purple; disc flowers yellow; pappus single, brownish

Fruits:

achene hairy

ASTER COMPLEX KEY FOR SPECIES FOUND IN SASKATCHEWAN
*(SPECIES PREVIOUSLY NAMED ASTER)*

1 Basal and lower stem leaves heart-shaped and stalked	Symphyotrichum ciliatum
1 Basal and lower stem leaves tapering at base, sessile to subsessile	2

2 Rays inconspicuous or absent	Symphyotrichum ciliatum (A. brachyactis)
2 Rays conspicuous	3

3 Bracts glandular, sometimes also otherwise hairy	4
3 Bracts not glandular, but may be hairy	7

4 Leaves toothed	Eurybia conspicua
4 Leaves entire or nearly so, margins at most with sharp, straight hairs	5

5 Stem leaves linear; sessile (lower ones stalked)	Almutaster pauciflorus
5 Stem leaves lance-shaped all sessile to clasping	6

6 Inflorescence stalks short; inflorescence compact	Symphyotrichum novae-angliae
6 Inflorescence stalks elongate; inflorescence loose	Canadanthus modestus

7 Pappus double	Doellingeria umbellata (var. pubens if leaf puberulent underneath)
7 Pappus single	8

8 Bracts with spiny tips	9
8 Bracts without spiny tips	10

9 Heads small; bracts 2 – 5 mm high, overlapping; rays 10 – 20	Symphyotrichum ericoides var. ericoides
9 Heads larger; bracts 5 – 8 mm high, bracts not strongly overlapping; rays 22 - 35	Symphyotrichum falcatum var. falcatum

10 Leaves firm; bracts hard or firm, thickened at base, green-tipped	11
10 Leaves thin and soft; bracts thin and scarious, not markedly thickened at base	12

11 Plants < 50 cm tall; leaves linear to narrowly oblong, entire	Oligoneuron album
11 Plants 40 – 100 cm tall; leaves oval to lance-shaped	Symphyotrichum laeve var. laeve

12 Stem leaves strongly clasping at base	Symphyotrichum puniceum var. puniceum
12 Stem leaves sessile, scarcely clasping to not at all clasping with ear-like lobes (if half clasping, not abruptly contracted to a winged petiole)	13

13 Rays white	Symphyotrichum lanceolatum var. lanceolatum
13 Rays purple or pink, rarely white	14

14 Bracts subequal	Symphyotrichum eatonii
14 Bracts unequal	15

15 Stems stout, to > 2 m tall; leaves lance-shaped to broadest at the middle	Symphyotrichum prenanthoides
15 Stems slender, < 1 m tall; leaves linear to lance-shaped	16

16 Leaves firm; bracts pointing downward	Symphyotrichum adscendens
16 Leaves relatively thin; bracts not pointing downward	17

17 Leaves mostly 2 – 5 mm wide; heads few (<10)	Symphyotrichum boreale
17 Leaves wider; heads > 10	Symphyotrichum lanceolatum var. hesperium