Identification by Microscopy of a Natural Hybrid between Portuguese Digitalis Species

Digitalis purpurea L. and Digitalis thapsi L. (Iberian endemism) are two well known Portuguese species that contain cardiac glycosides. Last year we found some specimens in the Northeast region of Portugal that appeared to us to be natural hybrids between D. purpurea and D. thapsi. In consequence, morphological, genetic and chemical experimental work was performed, involving a minimum of 30 samples of each plant species collected in this geographic area. Preliminary results of this work have been published.