Hosts of Struthanthus flexicaulis (Loranthaceae) in ironstone outcrops in the Quadrilatero Ferrifero, Minas Gerais

Abstract

Parasitic plants constitute an interesting study template for several botanical and ecological in the studies. In Brazil, about 100 species of Loranthaceae have been described, among which several in the genus Struthanthus, aerial hemiparasites characterized by an haustorial root system. We evaluated the host specificity of S. flexicaulis Mart. in a 9-ha area of high-altitude ironstone fields in the “Iron Quadrangle”, MG. The plant community develops over canga couraçada, a compact substrate rich in heavy metals, with low levels of moisture and organic matter. Of the 85 vascular plant species that occur in the area, 44, distributed among 19 families, are parasitized by S. flexicaulis, and one is used only as support. Phanerophytes were the most common host life-form. The lack of specificity is common to other Loranthaceae, and appropriate for a resource-heterogeneous environment, where host specificity would not be advantageous.