ORCHIS LATIFOLIA. IN BRITAIN' 3 



such uniformity of type as to give fair presumption that it is pure, 

 and the second, whether, when it is found growing with other forms, 

 it is bound to be a hybrid. 



On the first point, Col. Godfery (Journ. Bot. 1919, 138) quotes 

 abundant evidence of the occurrence on the Continent of O. latifolia 

 in plenty, of perfectly regular type, with spotted leaves, where no 

 O. metadata could be found. If this species is thus certified for the 

 Continent, it may very well be taken as probable that the very 

 similar forms found in Britain are also true latifolia, even though 

 they may be proved to be of slightly divergent types. 



If of hybrid derivation, the prevalent forms would have to be 

 referred to O. praetermissa and O. macidata for their parentage. 

 This, however, would not hold good in the case of a fairly large 

 batch of plants of O. latifolia which grows near the railway-line 

 close to Borth. Here are many dark forms along with some lighter 

 ones which may be hybrids, where O. ericetoram is present, but 

 no trace of O. praetermissa. At some distance, in the bog, O. incar- 

 nata grows, with pale leaves, usually very narrow ; but we should 

 doubt its influence here. There is at least the possibility that 

 O. latifolia is pure. Wherever else we have found it hitherto, 

 O. prcstermissa has been alongside. 



Taking up the second point, we think that our extended note on 

 the bearing of the Mendelian theory on our problem has shown that 

 a true species may arise from a cross, as well as from a mutation or 

 series of mutations. Apart from experimental crossing, the pure 

 forms could only be detected by such facts as their persistence through 

 several generations, which would afford a presumption that they were 

 breeding true, and their wide distribution, taken along with dis- 

 tinctness and uniformity of type. As our own preference is decidedly 

 for the mutation theory of their origin, we may say here that the 

 bold and distinct type of lip-pattern of O. latifolia does not by anv 

 means suggest to us a cross. Mr. 11. D. Laurie, M.A., of Aberyst- 

 wyth College, has suggested that the species may be the result 

 of a mutation in the direction of intensified pigmentation, the spots 

 on the leaves as well as the heavier lip-pattern showing in a two-fold 

 way the outcome of some germinal mutation — probably from O. prce- 

 termissa. The fact that O. latifolia itself appears to cross very 

 freely is also somewhat in favour of its being a true species. Of 

 course, if it be granted that the forms are due to mutation, the 

 specific rank follows ; for we need a name for the segregate. Even 

 if the view be taken that there is extreme mutation, and that the 

 forms are in a state of " polymorphic mixture," still the mixture is 

 confined to a certain limited range of forms, and we need a name for 

 the fluid aggregate, and we need to describe its chief types, if 

 not for ourselves, then for those who come after us, who will have to 

 note the ultimate outcome of the evolution of the forms. In his 

 article in Journ. Bot., Dec. 1920, Col. Godfery deals with the matter 

 from a different point of view, and perhaps better: see p. 289 (3). 



As hitherto generally accepted, the characters by which O. lati- 

 folia may be roughly distinguished from other forms are as follows : — 

 The sepals are erect as in O. incarnata, purpurclla, and praetermissa — • 



b 2 



