Harper’s dodder

Stems orange-yellow, filiform. Inflorescences loose, corymbi­form; bracts at base of clusters 1, at base of pedicels 0(or 1), ovate-triangular, membranous, margins entire, apex acute. Ped­icels 0.5–2.5(–3) mm. Flowers 4(or 5)-merous, 0.9–1.1(–1.5) mm, fleshy, corolla lobes papillate; calyx brownish yellow, angled, cupulate, equaling corolla tube length, divided 1/2–2/3 its length, ± reticulate, rarely shiny, lobes broadly ovate-rhombic, bases ± auriculate, overlapping, forming prominent angles at sinuses, margins entire, midvein ± carinate, apex rounded; corolla white, drying cream to brownish, 0.9–1.2 mm, tube campanulate, 0.5–0.7 mm, not saccate, lobes reflexed, triangular-ovate, equaling corolla tube length, margins entire, apex subacute to acute, inflexed; infrastaminal scales narrowly oblong to obovate, 0.6–0.9 mm, equaling or longer than corolla tube length, bridged at 0.2–0.3 mm, rounded, sparsely fimbriate, fimbriae 0.1–0.3 mm; stamens exserted, slightly shorter than corolla lobes; filaments 0.1–0.2 mm; anthers 0.2–0.3 × 0.2–0.3 mm; styles filiform, 0.5–0.9 mm, shorter than ovary. Capsules globose to ovoid, 1.2–2.3 × 1.2–1.6 mm, not thickened around relatively small to moderately large interstylar aperture, ± translucent, withered corolla enveloping 1/4–1/3 of base, indehiscent. Seeds 1 or 2, subglobose, with longitudinal groove on adaxial face, 0.9–1.1 × 0.8–1.1 mm, hilum region terminal.

Flowering Sep–Nov. Hosts: Bigelowia nuttallii, Croton michauxii var. elliptica, Helianthus longifolius, Hypericum gentianoides, Liatris microcephala, and others; sandstone, less frequently, granite outcrops; of conservation concern; 200–600 m; Ala., Ga.

Cuscuta harperi is closely allied with C. pentagona (M. Costea et al. 2015), from which it differs in smaller, four-merous flowers.