Dactylorhiza sect. Dactylorhiza

Efimov, Petr, 2025, An update of the taxonomic system of Dactylorhiza (Orchidaceae, Orchideae), Phytotaxa 691 (3), pp. 260-270 : 265-266

6. Dactylorhiza sect. Dactylorhiza

Type:— D. umbrosa (Kar. & Kir.) Nevski (perhaps a synonym of D. salina (Turcz. ex Lindl.) Soó ).

= Dactylorchis [sect. Maculatae ] subsect. Incarnatae Vermeulen (1947: 65); (Verm.) Soó (1960: 337), comb. inval. (Art. 41.5). ≡ Dactylorhiza sect. Incarnatae (Verm.) Quentin (1998: 406) ; Eccarius (2016: 188), nom. superfl. Type: Dactylorchis incarnata .

= Orchis sect. Klingeanthus Schltr. in Keller & Schlechter (1928: 160). Type: O. incarnata L., selected here. Schlechter considered this group to embrace all of the genus Dactylorhiza in the current meaning except for D. iberica and D. viridis . Nevski (1935) largely followed this classification but excluded from it D. sambucina and its allies. The typification here aims to place sect. Klingeanthus as closely as possible to the generic type, to minimize any possible future nomenclatural inconsistencies. Dactylorhiza incarnata was selected for that purpose because neither D. salina nor D. umbrosa was listed by Schlechter.

= Dactylorhiza ser. Orientales Nelson (1979: 592) . Type: D. cilicica (Klinge) Soó (perhaps a synonym of D. salina (Turcz. ex Lindl.) Soó ).

= Dactylorhiza ser. Septentrionales Nelson (1979: 593) . Type: D. incarnata (L.) Soó.

= Orchis [sect. Androrchis ] [stat. indef.] Latifoliae Reichenbach (1851: 35 , 51). ≡ Orchis [subgen. Dactylorchis ] subsect. Latifoliae (Rchb. f.) Camus, Bergon & Camus (1908: 173) ; Pugsley (1935: 576), comb. superfl. ≡ Orchis [subgen. Dactylorchis ] sect. Latifoliae [‘ Latifolii’] (E.G.Camus, Bergon & A.Camus) Keller & Soó (1932: 132). ≡ Dactylorhiza sect. Latifoliae (Rchb.f.) Smoljaninova (1976: 52) . ≡ Dactylorhiza [sect. Dactylorhiza ] subsect. Latifoliae (Rchb.f.) Averyanov (1983b: 1162) . Type: Orchis latifolia L. (for information about the rank of Reichenbach’s name, see notes under sect. Iberanthus ). The exact taxonomic position of sect. Latifoliae may be questioned due to the problematic interpretation of its type, Orchis latifolia , which is a rejected name following the proposal by Pedersen (2000), but the sectional name based on it is legitimate (Art. 56.1, note 1). According to different typifications of this name, it was considered a synonym of D. incarnata , D. sambucina or D. majalis , all of which are in different sections. Here we follow the earliest typification, which makes it a synonym of D. incarnata , but it should be kept in mind that if this typification is not accepted (possible reasons for that are outlined by Pedersen (2000)), then sect. Latifoliae will change its taxonomic position. If Orchis latifolia is recognised as a synonym of D. sambucina , then sect. Latifoliae will have priority over sect. Sambucinae. If Orchis latifolia is recognised as a synonym of D. majalis (as in Reichenbach’s conception), then sect. Latifoliae will have priority over sect. Angustifoliae .

– Dactylorhiza [sect. Maculatae ] subsect. Eulatifoliae Soó (1960: 341), nom. inval. (Art. 21.3).

Section Dactylorhiza is understood here in the narrow sense, corresponding to subsection Dactylorhiza in Averyanov’s classification (1990). It includes mostly diploid taxa, but also some allotetraploids combining incarnata - and euxina - genomes ( D. armeniaca ). It is not conclusively understood whether D. armeniaca is a bona fide species like the allotetraploids originating from incarnata - and fuchsii - genomes or rather a set of independently formed hybrids and reciprocal crosses with parents. It was described by Hedrén (2001) from Turkey, and there are some fragmentary data that in Georgia it is a ‘good’ species ( Akhalkatsi et al. 2007; Kreutz 2019); there is also a solitary report from the Russian Caucasus ( Shipunov et al. 2004).

Eccarius (2016) subdivided this group into two, sect. Dactylorhiza s.str., and sect. Incarnata . Such splitting cannot be followed because the types of both sections, D. salina s.l. and D. incarnata , are closely related and often hybridise, e.g. vast areas of Central Asia may be inhabited by plants with intermediate morphology. Brandrud et al. (2020) established that the divergence between D. salina s.l. (as ‘ D. umbrosa ’) and D. incarnata occurred only c. two million years ago, which is much less than, e.g., between D. fuchsii and D. foliosa , taxa that are placed in the same (sub)section in all classifications.

In fact, there is another species in section Dactylorhiza , D. euxina , which can be more reasonably segregated to a section of its own (but such a section has not yet formally described). The estimation of divergence time of D. euxina is 4–5 million years ( Brandrud et al. 2020). However, such splitting is again not recommended because of the following: 1) divergence times and morphological differentiation between other sections are still larger, so this will be a pair of closely related sections; 2) in all earlier classifications, D. salina s.l. and D. euxina were placed in the same section (or subsection), and 3) (most importantly) their separation will cause major taxonomic disruption in the classification, requiring two additional sections to be established, one for D. urvilleana and another for D. armeniaca . This is because D. urvilleana is an allotetraploid derived from crosses between D. euxina and D. saccifera , and D. armeniaca is derived from crosses between D. euxina and D. incarnata (Hedrén 2001, 2002).

Ca. 8 species: Dactylorhiza armeniaca Hedrén (possibly a set of independent hybrids, see above), D. euxina (Nevski) Czerep. , D. hatagirea (D.Don) Soó , D. incarnata (L.) Soó, D. kafiriana Renz , D. ochroleuca (Wüstnei ex Boll) Holub (perhaps included in D. incarnata ), D. osmanica (Klinge) Soó , D. salina (Turcz. ex Lindl.) Soó (here understood in broad sense including D. umbrosa (Kar. & Kir.) Nevski , D. magna (Czerniak.) Ikonn. , D. cilicica (Klinge) Soó and many others, which is only a preliminary approach in the absence of a detailed revision of the group).