Scientific Family
Asteraceae
Synonyms
Aster spinosus, Chloracantha spinosa var. spinosa, Erigeron ortegae, Leucosyris spinosa
Other common names
spiny aster
Mexican devilweed
devilweed aster
aster
Plant type
Forbs and Subshrubs
Origin
Native
Lifecycle
Perennial
Height
1 to 9 feet
Riparian
Yes
Perennial herb to sub-shrub, stoutly rhizomatous and forming colonies; usually thorny at the base but often thornless above; stems green, erect; lateral branches sharply ascending, wand-like.
Ray and disc flowers. Stems form erect, much-branched, almost leafless, pale green, broom-like clumps, deep seated rhizomes, 1 to 9 feet tall. Basal leaves long and narrow to spatula shaped, to 2 inches long, upper leaves tiny and scale-like.
Habitat
Found in moist, saline soil, on riverbanks, bottomlands, saline flats, ditches, and irrigation channels.
Plant Community
Riparian
Disturbed Areas
Low elevation
1000
High elevation
4200
Flower Characteristics
Flowers are loosely branched, mature from bottom up; ray flowers 20 to 33, white, and 1/4 inch; disc flowers 20 to 70, corollas yellow; whorl of bracts wrapped around the flower head, 1/4 inch high, lance-shaped, with thin, transparent margins.
Flower color
White and yellow
Flower shape
Daisy or dandelion-like
Tubular
No
First bloom month
May
Last bloom month
October
Flower clusters
None
Leaf and Stem Characteristics
Leaves attached directly to stem without a supporting stalk, early withering before flowering, 1 prominent vein, inverted lance-shaped with narrow end at attachment, up to 2 inches long, margins smooth or rarely have 1 to 2 pairs of small teeth.
Leaf type
Simple
Leaf color
Pale green
Leaf shape
Narrow
Leaf margin
Smooth
Leaves clasp
Yes
Leaf hairs
None
Spines
No
Fruit and Seed Characteristics
Small, dry fruit is smooth, hairless, 1/4 inch long, spindle to cylinder-shaped, slightly compressed, and 5-veined, topped with 30 to 60 persistent, white to tan sepals of short, stiff bristles usually in 1 to 2 series, plus shorter outer bristles.
Fruit type
Achene
Fruit color
White to tan