Ambrosia confertiflora – Weakleaf Bur Ragweed
Scientific Name: Ambrosia confertiflora
Synonym: Franseria confertiflora
Common Names: Weakleaf Bur Ragweed, Weakleaf Burr-Ragweed, Slimleaf Bursage, Slender Ragweed
Growth Habit: Herb/Forb
Arizona Native Status: Native
Habitat: Desert, Upland
Flower Color: Dull yellowish, Greenish
Flowering Season: Spring, Summer, Fall
Height: To 3 feet (91 cm) tall, but usually less
Description: The staminate (male) flower heads are in terminal and lateral flower spikes, while the pistillate (female) flower heads are clustered below them at the leaf axils. The flowers are wind-pollinated and are followed by burs with a few, short, hooked spines. The leaves have petioles with lobed wings and are grayish green in color, mostly alternate, covered in silky grayish hair, lanceolate to ovate in shape, and 2-4 pinnately lobed with narrowly lanceolate lobes. The upright stems grow from rhizome-like roots and are hairy or bristly and green to reddish brown in color.
These weedy plants are often found growing in disturbed areas.
Allergenic – The male flowers have highly allergenic pollen.
Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Family: Asteraceae – Aster family
Genus: Ambrosia L. – ragweed
Species: Ambrosia confertiflora DC. – weakleaf bur ragweed
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