THE PR01>.LI':Nr OF TUK HI{TTrSTI MARSK ORCirTDS 280 



The (lilliculties in connection with tlie l>ritisli marsh orchids liave 

 mainly arisen from the following causes : — 



(I) The suggestion that O. prwtennisisa Druce is the true 

 O. laiifoUn L., a proposition for which no dehnite proof is forth- 

 coming, and which is in o})position to Continental experience and 

 ()[)inion. 



(2j The supposition that the spotted-leaved British marsh orchid 

 is a hybrid between prcctermisHa and maculata, whereas it appears to 

 l)e simply O. latifolia L. 



(3) The confusion which has arisen througli the erroneous identi- 

 fication of the hybrids prcefermissa X maculata and incariiataXmacu- 

 lafa as O. latifolia L. In view of the facts that i^rcdtermissa and 

 incarnata are both closely allied to latifolia, and that the leaf- 

 8))otting and also the li})-markings of maculata are very similar 

 to those of latifolia, it will be seen that hybrids of either ^^r«^- 

 termissa or incarnata, into which the above two characteristics 

 of maculata have been introduced by the part parentage of the 

 latter species, are bound to bear a superficial resemblance to lati- 

 folia. J^ut to assume that O. latifolia L. is therefore prceter- 

 missa X maculata is to base a wide generalisation on observations 

 limited to a restricted and insular flora, and is a conclusion absolutely 

 at variance with the fact that latifolia is a very widely distributed 

 European species which grows in immense numbers where both the 

 su[)posed parents are non-existent. 



it is not only in England that the marsh orchids present diffi- 

 culties. Dr. Keller wrote on March 15th, 1920 : "The more one studies 

 the group latifolia-Traiinsteineri, the more perplexed one becomes. 

 1 believe, howev^er, whilst reserving final judgment, that true latifolia 

 always has spotted leaves, and that the forms with narrow leaves 

 witliout spots are to be classed under the extremely polymor])hic 

 species anc/ustifolia or Tratinsteineri. 1 possess forms from Lychen 

 ((jiermany), the water-colour drawing of which is almost identical 

 with yours representing 'prcdtermissa, but these forms from Lychen 

 were sent to me as Traunsteineri.'" As 1 do not know the latter 

 s[)ecies, I cannot express any opinion on Dr. Keller's suggestion, but 

 it appears always to have narrow leaves, which is not at all the case 

 with jyrcetermissa. I found two or three j^lants of the latter with 

 quite narrow leaves at Punfield, near Swanage, though the broader- 

 leaved type was more numerous. Dr. Keller, Aarau, Switzerland, is 

 anxious to receive specimens of prcetermissa, dispatched immediately 

 aft(r gathering, ioY comparison with Continental forms. Nos. 16-19 

 above would, I think, if found in England, have been classed with 

 2)r(Etermissa rather than with latifolia, though not typical enough 

 to be definitel}'' assigned to it. They were exceptional specimens — 

 no more were found like tliem — and were undoubtedly only individual 

 variations of latifolia in the direction of prcetermissa. This expres- 

 sion, however, though convenient, is misleading. Probably species A 

 does not vary in the direction of species B, but only in the direction 

 of their common ancestor, C. There is always the possibility that 

 some diameter of C, which has always been transmitted to B, but 

 has long been elimii^'ated from, or become latent in A, may exception- 

 ally re-appear in the latter, either through partial reversion, or by 



