Two new combinations in Euploca Nutt. (Heliotropiaceae, Boraginales) and a conspectus of the species of the Guiana Shield area

Abstract. Heliotropium foliatum and Tournefortia humilis are transferred to Euploca Nutt. respectively as Euploca foliata comb. n. and Euploca humilis comb. n. A collection from Guyana has been recently identified as Euploca humistrata, a species previously considered a Brazilian endemic. A collection from French Guiana documents for the first time the species in that country. A key to the species of the Guiana Shield area is given. The species of Euploca from the Guiana Shield are listed with synonymy and a brief description: Euploca filiformis, Euploca humilis, Euploca humistrata, Euploca lagoensis, Euploca polyphylla, Euploca procumbens.