Dactylorhiza Necker ex Nevski, 1935

D. M. Moore (ed.), 1980, CCIII Orchidaceae, Flora Europaea, Vol 5: Alismataceae to Orchidaceae, Camebridge: Cambridge University Press, pp. 325-350 : 333

19. Dactylorhiza Necker ex Nevski 2**S.

Tubers 2-3, usually palmately 2- to 5-fid, more or less elongated at the apex, rarely oblong-cylindrical and shallowly 2(-4)-fid. Perianth-segments free, equal or the inner smaller, patent or deflexed, rarely convergent. Labellum porrect or slightly decurved. Spur present. Lower bracts herbaceous. Rostellum 3-lobed, the middle lobe short, lamelliform. Viscidia in one simple bursicle.

A taxonomically difficult genus in which many species show marked variation within and between different populations and in which interspecific hybrids are both frequent and of generally high fertility. Amongst the commonest hybrids are 8x4, 8 x 6(e), 8x12, 6(d) x 4, 6(d) x 12, 6(e) x 11(b) and 12 x 11(b); hybrid plants can be more frequent, and more vigorous, than the parent species in a population, especially in the cases of 6(e) x 11(b) and 6(e) x 12. In some instances populations of more or less stabilized hybrid segregates are known, as in 6(e) x 12, while it has been suggested that some taxa, such as some subspecies of 6, have originated in this way. Intergeneric hybrids are known between 6(d) and 6(e) and both Coeloglossum viride and Gymnadenia conopsea .

Literature: J. Heslop-Harrison, Trans. Proc. Bot. Soc. Edinb. 35: 26-66 (1948); Svensk Bot. Tidskr. 45: 608-635 (1951); Watsonia 2: 371-391 (1953); Ber. Geobot. Inst. Rubel {Zürich) 1953: 53-82 (1954). E. Nelson, Monographie und Ikonographie der Gattung Dactylorhiza . Zürich. 1976. R. von Soö, Bot. Arch. {Leipzig) 23: 61-83 (1928); Ann. Univ. Sei. Budapest. Rolando Eötvös 3: 335-357 (1960); Jahresb. Naturw. Ver. Wuppertal 25: 37-48 (1972). P. Vermeulen, Studies on Dactylorchids. Utrecht. 1947. K. Senghas, Jahresb. Naturw. Ver. Wuppertal 21-22: 32-67 (1968).

1 All 5 perianth-segments convergent into a galea; stem with stolons 1. iberica

1 Lateral outer perianth-segments not forming part of galea; stolons absent

2 Tubers shallowly 2- to 4-fid or -dentate at apex, rarely sub­ entire

3 Stem with 4-5 distant leaves in lower half; spur not more than 15 mm 2. sambucina

3 Stem with up to 10 leaves in a lax basal rosette; spur 12-25 mm 3. sulphurea

2 Tubers deeply 2- to 5-fid

4 Lateral outer perianth-segments patent; stem usually solid (11-13). maculata group

4 Lateral outer perianth-segments suberect; stem usually hollow (4-10). incarnata group