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Laennecia coulteri - Coulter's horseweed

Scientific Family
Asteraceae
Synonyms
Conyza coulteri, C. coulteri var. virgata, Eschenbachia coulteri
Other common names
Coulter's Woolwort
annual horsetail
conyza
Plant type
Forbs and Subshrubs
Origin
Native
Lifecycle
Annual
Height
4 to 40 inches
Riparian
Yes

Herb with taproot; stems glandular or covered with sticky hairs which resemble spider's web (arachnoid).

Stems and leaves glandular or viscid; leaves more or less serrated or divided into deep narrow irregular segments. Flower heads without ray flowers, the disc flower are about half as long as the tuft of hairs on each seed.

Habitat

Found in ditch banks, dry stream beds and disturbed sites.

Plant Community
Desert Scrub
Disturbed Areas
Grasslands
Interior Chaparral
Montane Conifer Forest
Pinyon Juniper Woodlands
Riparian
Low elevation
1500
High elevation
9000

Flower Characteristics

Disc flowers only along elongated, branched stems, 5 to 20 per flower stem; 2 to 5 bracts (phyllaries) cone-shaped, 1/8 inch diameter; 60 to 100 female whitish flowers ring the edges of flower heads.

Flower color
Whitish
Flower shape
Daisy or dandelion-like
Tubular
No
First bloom month
September
Last bloom month
October
Flower clusters
Elongated

Leaf and Stem Characteristics

When plant is young, leaves form a densely hairy basal rosette; after plant bolts, leaves alternate along the stem, mostly sessile and clasping; blades oblong, 3/4 to 2 inches long and 1/4 to 3/4 inch wide, many irregularly toothed or obscurely lobed.

Leaf type
Simple
Leaf color
Green
Leaf shape
Narrow
Leaf margin
Toothed
Leaf attachment
Basal & Alternate
Leaves clasp
Yes
Leaf hairs
Leaves & stems
Spines
No

Fruit and Seed Characteristics

Achenes <1/16 inch long, pale tan, topped with a pappus of 10 to 30 fragile and easily deciduous whitish bristles.

Fruit type
Achene
Fruit color
Whitish