101 THE JOUKNVL OF HOT A NY 



The only doubt in my mind is, not whether E. Jlaclleri is a 

 distinct species, but whether it does not constitute a separate genus. 

 It must be admitted that differences in the structure and co-ordina- 

 tion of the reproductive organs furnish generic rather than specific 

 characters. But it is manifestly undesirable to create a new genus 

 except on quite unassailable grounds, and the whole facies of the 

 plant is so exactly that of an Epipactis that it seems preferable to 

 widen our conception of that genus rather than to found a question- 

 able genus on a single type. 



Dr. Rudolf Sehlechter is against the creation of a new genus, but 

 reserves his opinion as to the question of specific rank. He is 

 inclined to regard Muelleri as a biological variety of E. latifolia — - 

 that is to say, that it is latifolia modified for self-fertilisation. It is 

 easy to conceive that an Epipactis could become self-fertilising 

 through the pollen becoming very friable and falling into the flower, 

 as in the English E. viridiJJora var. dutlensis, or through the 

 pollinia sliding over the upper edge of the stigma as in leptochUa 

 (Journ. Bot. 1920, p. 33) and in microphylla, but it is hard to 

 believe that modification of each individual organ, and their co- 

 ordination on a different plan, should be either necessary or probable 

 to secure a result which has actually been so much more simply 

 attained in the above species of Epipactis. 



Darwin showed that cross-fertilisation is superior to self-fertilisa- 

 tion : " It is hardly an exaggeration to say that Nature tells us in 

 the most emphatic manner, that she abhors perpetual self-fertilisa- 

 tion " (Fert. Orch. 1890, p. 293). He explains the self-fertilisation 

 of O. apifera and E. viridiflora as probably due to their being 

 threatened with extinction through lack of insect visits, and indeed it 

 is hard to believe that a cross-fertilised plant should be modified for 

 self-fertilisation without some cogent reason of this kind. But why 

 should latifolia need to become self-fertilised ? It is the most 

 abundant and widely spi'ead of all species of Epipactis, and is un- 

 usually well visited by insects. Why should it give up successful 

 cross-fertilisation for an admittedly inferior method ? We are met 

 at the outset by an inherent improbability. Further, if Mxellcri is 

 a biological variation of latifolia with a view to increased fertility 

 through self-fertilisation, it has entirely failed, at any rate at 

 Thorenc, to bring about this result. It is restricted to one small 

 wood in the midst of an immense area of similar woodland. Per- 

 sistent search throughout the whole of its flowering-season only 

 produced eleven specimens, while it was surrounded on every side by 

 hundreds of flourishing latifolia. When an insect-fertilised plant, 

 such as O. apifera or Ceplialanthcra pallens becomes mainly self- 

 fertilising, it usually grows in considerable numbers, and is often 

 very abundant, as might be expected from a plant in which nearly 

 every flower produces a capsule. Is any instance known of an orchid 

 in which the self-fertilised form is rare, and the cross-fertilised 

 plentiful ? Muelleri, at Thorenc, appears much more like the 

 remnant of a disappearing species than a plant seeking to raise its 

 numerical standard by the adoption of self-fertilisation. It suggests 

 a case of arrested development. 



