Plant Species Associated with a Regionally Rare Hemiparasitic Plant, Pedicularis lanceolata (Orobanchaceae), Throughout Its Geographic Range

Abstract

Abstract Typically, non-native invasive plant species are considered a threat to rare native plants, but this generalization may not hold true for rare parasitic plants that depend upon host plants to complete their life cycles. It is essential to know what plant species a particular hemiparasitic species associates with in the field, in order to determine host plant preferences and to make broader inferences about host plants. Pedicularis lanceolata is a hemiparasite that is regionally rare in New England and the southeastern margins of its range, but more abundant in the core of its range in the Midwest. I sought to compare the species associated with P. lanceolata in the core and margins of its range to determine if marginal populations have different associates from core populations. I hypothesized that P. lanceolata may be rare in the eastern United States because it encounters fewer suitable associates, and potentially more competitive invasive species, at the margins of its range than at the center...