Cuscuta cuspidata Engelm., cusp dodder, cuspidate dodder. Annual parasitic vine, twining, flexible–stemmed, attached to host stem by haustoria; shoots essentially leafless, light orange (lacking chlorophyll), glabrous
Stems threadlike and cylindric, 0.3—0.35 mm diameter, fleshy, light orange (greenish), smooth but becoming knobby where haustoria initiate.
Leaves helically alternate, simple, sessile, without stipules; blade appressed, awl–shaped, to 2 mm long, rounded on back
Inflorescence paniclelike condensed cymes, axillary, each cyme 2—many–flowered, bracteate, glabrous; cyme axes initially pale light green; bract subtending branchlet and bractlet subtending pedicel awl–shaped often keeled above midpoint, 1.5—2 mm long, white or greenish at base, cupped, acute at tip; pedicel at anthesis 0.4—1.5 mm long increasing to 2 mm in fruit; bracteoles subtending flower 2. cupped–ovate, ca. 1.3 × 1.3 mm, white.
Flower bisexual, radial, ca. 4 mm across (spreading corolla lobes) and 2 mm across (reflexed corolla lobes), receptacle pale green; calyx of 5 sepals essentially free at base, appressed to corolla and resembling bractlet and bracteoles, overlapping at base, cupped–ovate to cupped–elliptic, 1.5—1.7 × 1.5 mm, whitish, somewhat wavy on margins, lacking veins and papillae; corolla 5–lobed, ± 2.7 mm long, white lacking veins, with 5 appendages attached below midpoint; tube + throat bell–shaped, in range ca. 1.9 mm diameter; lobes spreading aging reflexed, acute–triangular, ca. 1.6 × 0.9 mm, not papillate, the appendages at anthesis ⊥ to tube bent inward and hiding ovary, membranous, wedge–shaped in outline and conspicuously fringed (fingerlike), ± 0.5 × 0.3 mm, white–translucent; stamens 5, fused to end of tube alternate with corolla lobes (just beneath sinuses), attached above corolla appendage; filaments erect, flattened on outer side, 0.8—1 mm long, white; anthers exserted, dorsifixed, dithecal, 0.6—0.7 mm long, orange, longitudinally dehiscent; pollen yellow–orange; nectary disc weakly defined surrounding basal 1/4 of ovary, green aging orangish; pistil 1; ovary superior, barrel–shaped aging spheroid, ca. 0.7 mm long, green aging pale green above midpoint, 2–chambered, each chamber with 2 yellow–green ovules; styles 2, in depression at top of ovary, suberect and somewhat divergent, unequal, ca. 2.5 mm and 3.1—3.2 mm long, white; stigmas positioned at different heights with 1 at top of anthers and the other at base of anthers, capitate, 0.3—0.4 mm diameter, orange.
Fruit berrylike capsule, in range (1—)2—4–seeded, papery and not dehiscing regularly, subspheroid, ca. 2 mm; calyx scarious, cupped around fruit.
Seed mostly 3–sided (2–sided if 2–seeded) with rounded outer face and flattish lateral faces, ca. 1.5 × 1 mm, dull orange–brown, rounded along edge.
A. C. Gibson