Henrik Ærenlund Pedersen’s research while affiliated with IT University of Copenhagen and other places

When Gunnar Seidenfaden died on 9 February 2001 he left all his orchid-related materials to the Botanical Museum and Library, University of Copenhagen. These materials included an unfinished manuscript for the present paper which was subsequently completed by the junior author. Thus, the present paper constitutes the final part in the series “Contributions to the Orchid Flora of Thailand” that was initiated in 1969. Like the preceding parts, no. XIV provides scattered information to update the taxonomy, nomenclature, and distribution knowledge of the Thai orchid flora. The following taxa are dealt with: Pecteilis hawkesiana (comb, nov.), Epipactis flava, Zeuxine longilabris, Dendrobium lamyaiae, Epigeneium chapaense, Glomera sp., Calanthe odora, Pelatantheria ctenoglossa, Macropodanthus alatus, Armodorum siamensis, Echioglossum simondii, and Acampe joiceyana (comb. nov.).

The new orchid genus Sirindhomia, named after H. R. H. Princess Maha Chakri Sirindhorn of Thailand, is established to accommodate three species from Thailand (Chiang Mai and Tak provinces), Myanmar (Shan State), and China (Yunnan province). Two new species are described and a new combination, based on Habenaria monophylla Collett & Hemsl., is made; all of the three species are illustrated, and a distribution map is provided. Sirindhomia belongs to subtribe Orchidinae and has an overall similarity with Ponerorchis, Hemipilia, and Amitostigma. However, it significantly differs in its column morphology which is more reminiscent of that found in the vegetatively distinct genus Orchis. The new species, Sirindhomia pulchella and S. mirabilis, seem to be local endemics, as they are only known from the Thai mountains Doi Chiang Dao and Khao Hua Mot, respectively. Sirindhomia monophylla, on the other hand, is known from a very large part of the range of the genus. All Sirindhomia species known are restricted to limestone mountains at 800–2200 m alt., mainly growing in rock crevices and among scrub as well as on grassy slopes. They flower from April to June.

Pedersen, H. Æ. : On the status and synonymy of the names Dactylorhiza majalis and D. incarnata (Orchidaceae) and their typification. ‐ Taxon 49: 539–544. 2000. ‐ ISSN 0040‐0262. In conjunction with a proposal to reject the name Orchis latifolia L. 1753 (Pedersen 2000), the nomenclature of the two species commonly known as Dactylorhiza majalis (Rchb.) P.F. Hunt & Summern, and D. incarnata (L.) Soó is examined. The basionyms, Orchis majalis Rchb. 1828 and O. incarnata L. 1755, respectively, are both considered to be legitimate. The former is lectotypified here, whilst Vermeulen's lectotypification of the latter is accepted. Orchis fistulosa Moench 1794, considered by Baumann & Künkele as the basionym for the correct name of the species here called Dactylorhiza majalis , is considered to be illegitimate ( O. latifolia pro syn.). Dactylorhiza strictifolia (Opiz) Rauschen is found to be a synonym of D. incarnata. Orchis comosa Scop. 1772, accepted by P. D. Sell as the basionym for the correct name of the species here called Dactylorhiza majalis , is here considered to be legitimate. However, a lectotype and an epitype designated in the present paper in effect place Orchis comosa in the synonymy of Dactylorhiza incarnata. In conclusion, the names Dactylorhiza incarnata and D. majalis should be accepted [assuming that the proposed rejection of Orchis latifolia is approved; otherwise, the name Dactylorhiza latifolia (L.) Soó must be recognised as the correct name for either D. incarnata, D. sambucina , or D. majalis –depending on its much‐debated typification]. However, if a wide species concept is applied, Orchis majalis Rchb. 1828 may be found conspecific with O. data Poiret 1786 [the basionym of Dactylorhiza elata (Poiret) Soó].