Cuscuta harperi Small

Harper's Dodder

Herb

Annual

Vascular

Harper's Dodder is a native annual twining vine in the Morning-Glory family (Convolvulaceae). It can be found in the northern third of Alabama. Harper's Dodder occurs on open, sunny, sandstone or granite outcrops. It is a holoparasite, lacking chlorophyll. The stems are thin, orangish-yellow in color, twisting around and attaching to host plants with specialized roots known as haustoria. The haustoria allow the Dodder to extract nutrients and water from the host. Leaves are alternate and reduced to small scales. The flowers are small (1 mm long), with 4 green-white sepals and 4 white petals with up-turned tips. The fruit is a small round capsule. Harper's Dodder is listed as a S2 species in Alabama (typically 6 to 20 occurrences, few remaining individuals, or factors demonstrably making it very vulnerable in the state), and globally as a G2G3 species (imperiled globally because of rarity (6 - 20 occurrences) or very vulnerable to extinction throughout its range because of other factors). It is restricted to sunny rock outcrops, and parasitizes a narrow range of species including Small Head Blazing Star (Liatris microcephala (Small) K. Schumann), Nuttall's Rayless Goldenrod (Bigelowia nuttallii L.C. Anderson), Longleaf Sunflower (Helianthus longifolius Pursh), Pineweed (Hypericum gentianoides (Linnaeus) Britton, Sterns & Poggenburg), and Outcrop Rushfoil (Croton willdenowii G.L. Webster).—A. Diamond

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Native S2 (State Rank) G2G3 (Global Rank)

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