1. Serapias caule multifolio multifloro published by Linnaeus in 1737 is a collective species comprising the species of the genera Epipactis and Cephalanthera in their modern meaning. The diagnosis is changed in Linnaeus’ later works but his opinion does not change until 1763. 2. In 1753 Serapias Helleborine is still the same collective species. Linnaeus’ herbarium specimen, which is determined as Serapias Helleborine latifolia is the Marsh Helleborine. 3. Under the influence of the work of Hudson (1762) Linnaeus changes his mind and in Species Plantarum ed. 2 (1763) the collective species is divided into Serapias latifolia Hudson for the species of the genus Epipactis and S. longifolia for those of the genus Cephalanthera Both species are collective ones. 4. After the publication of Haller’s paper in Act. helv. IV, 1760, in which the binary nomenclature is not yet followed, Linnaeus in 1767 in Syst. nat. ed. 12 divides Serapias latifolia Huds. into two species Serapias latifolia Huds. emend. L. for the Broad-leaved Helleborine and Serapias longifolia L. for the Marsh Helleborine. The epithet longifolia, however, had already been used by Hudson and therefore S. longifolia L. is a later homonym and must be rejected. 5. Serapias longifolia Huds. is renamed S. grandiflora by Linnaeus and therefore this name is a later synonym for S. longifolia Huds. and for reasons of priority must be rejected. S. rubra is now also mentioned. 6. Apparently Linnaeus revised the herbarium sheet of the Hortus Cliffbrtianus about 1767 (Syst. nat. ed. 12). This was a Marsh Helleborine and Linnaeus determines it as Serapias longifolia L. This plant can be seen as the type of S. longifolia L. (non S. longifolia Huds.!) but this name is not legitimate. 7. If a species is divided into two, the original epithet has to be kept or reinstated. Dividing Serapias Helleborine L. into two species the epithet had to be kept for S. latifolia Huds. In dividing this species again into two, one of the two retains the name S. Helleborine. 8. Linnaeus typifies the Marsh Helleborine with his determination Serapias longifolia L. as one part. For the other part, the Broad-leaved Helleborine, the name S. latifolia Huds. emend. L. is used but also in this case the eptihet Helleborine must be reinstated and so the name is S. Helleborine according to current usage. In this sense the name was used by Miller; S. Helleborine L. em. Mill. 9. The oldest legitimate epithet for the Marsh Helleborine is that of Miller palustre (1768) and combined with the genus name Epipactis the name for this species has to be Epipactis palustris (Mill.) Crantz (1769) and the type for this is the plant depicted in Flora danica, tab. 267, because this is given as a synonym by Crantz. 10. The oldest legitimate epithet for the Broad-leaved Helleborine is Helleborine and the name of the species in the genus Epipactis is now Epipactis Helleborine (L. em. Mill.) Crantz. The type of the species is the plant depicted by Haller in Historia Stirpium Helvetiae, vol. 11, tab. 40. I am much indebted to Mrs. G. King for her valuable help with the correction of the English translation and to Dr. F. A. Stafleu for his advices.