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Flaveria trinervia - clustered yellowtops

Scientific Family
Asteraceae
Synonyms
Brotera contrayerba, B. sprengelii, B. trinervata, Eupatorium chilense, Flaveria repanda, Oedera trinervia
Other common names
speedyweed
yellow twinstem
clusterflower
clustered flaveria
Gaika weed
Plant type
Forbs and Subshrubs
Origin
Native
Lifecycle
Annual
Similar species
Flaveria australasica
Height
To nearly 4 feet
Riparian
Yes

Erect, weedy annual with branches and stems that are often red-tinged. The round to lance-shaped green leaves are 3-veined and up to 8 inches long. The flowering stalk is a large, dense, round cluster of many tiny pale yellow or whitish flower heads.

Erect annual; leaves stemmed, toothed, rounded to lance-like; 30 to 300 flower heads, usually just 1 flower each, either pale yellow or whitish ray or disc flowers, in dense, stemless, axillary clusters; sepals 0; bracts usually 2.

Habitat

Grows in many types of wet habitats including those with saline, clay and gypsum (high in calcium and sulfur) rich soils. Found in moist roadside soils, waste places, stream banks and sometimes in cultivated areas.

Plant Community
Disturbed Areas
Riparian
Low elevation
0
High elevation
4000

Flower Characteristics

Flowering stalk is a large, dense, tight head-like cluster (glomerule) of many small flower heads. Each flower head usually contains 1 tiny tube-like yellow disc floret in the center with 1 yellow or whitish strap-shaped ray floret around the periphery.

Flower color
Pale yellow or whitish
Flower shape
Daisy or dandelion-like
Tubular
No
First bloom month
May
Last bloom month
November
Flower clusters
Rounded

Leaf and Stem Characteristics

Leaves grow in opposite pairs around the stem, sometimes their bases are fused together (connate). Leaves often have stalks but those on the upper stem may be stalkless. Leaf edges usually have tiny widely spaced teeth. Stems are often red-tinged.

Leaf type
Simple
Leaf color
Green
Leaf shape
Round or oval
Leaf margin
Toothed
Leaf attachment
Opposite
Leaves clasp
Yes
Leaf hairs
None
Spines
No

Fruit and Seed Characteristics

Fruit is about 1/16 inch long, black, dry, with an oblong shape and 10 ribs on its surface. It doesn't split open at maturity to release the seed and doesn't have a hairy tuft (pappus) on its tip.

Fruit type
Achene
Fruit color
Black

1 seed is produced by the fruit.