ORCHIS LATIFOLTA IN BRITAIN 7 



and that a truly typical specimen of it cannot be confounded with 

 any other species or with first-generation hybrids ; but that it is 

 extremely variable — some of the forms resembling no other species, 

 some verging more towards O. prcetermissa and some towards 

 O. maculata, but at the same time not in any sense identical with 

 these species. 



P.S. — Since the above article was completed, Dr. Druce has published 

 (B. E. C. Report, 1919, p. 90S) a long and interesting note, in which 

 he combats, as we think quite successfully, Mr. Rolfe's contention 

 that O. prcetermissa is the true O. latifolia L. Col. Godfery has 

 also written in this Journal for December last strongly urging the 

 recognition of O. latifolia L. as a valid species. We believe that on 

 all the main points we are in accord with Col. Godfery 's views with 

 regard to the British plants. In this and his preceding article ( Journ. 

 Bot. 1919, 137-142) Godfery has produced ample evidence of the 

 occurrence of a pure O. latifolia on the Continent. It is practically 

 certain that British plants precisely similar to these belong to the 

 same species. 



THE LICHEN AS TRANSMIGRANT. 



By A. H. Church. 



Once the probability of the direct progression of the Lichen from 

 the sea has been put on a reasonable basis, from the analysis of its 

 present somewhat secondary and recapitulatory organization, it 

 becomes possible to make a fresh start at the right end of the story ; 

 and to build up an account of the sequence of the progression, 

 beo-inning at the marine inception of the problems concerned, instead 

 of working backward from higher land-flora, as has been so often 

 attempted in dealing with lypotheses of the origin of the earlier 

 vegetation of the world-surface. All other vestigial relations of the 

 Lichen now acquire a new and vital interest. It is to the reproductive 

 phases and the stages of the life-cyle that one must look for further 

 suggestions as to the older marine chapters in the history of the race, 

 now seen to consist more probably of many polyphyletic and parallel 

 lines of early algal organism, similarly faced with the problems of the 

 transmigration at a common horizon. The intrusive and accessory 

 algal 'gonidia' may be largely omitted from consideration. It is 

 on the fungus-component, in its own antecedent algal condition, that 

 interest is specially concentrated; and this is commonly of veiy 

 normal Ascomycete habit, following again the presentation of what 

 may be referred on general principles to the earliest phase of the 

 Ascomycete progression. For example, consideration of the working- 

 mechanism of the ascus suggests that : — 



I. An open exposed hymenium, with asci discharging their con- 

 tent of 8 ascospores in a volley by hydrostatic tension, is presumably 

 the primitive method of spore-distribution in the group 1 ; and that 

 it was to this end that the ascus was elaborated in the first place 

 from a unilocular sporangium emitting flagellated zo'ids in an 



1 Buller (1909), Researches on Fungi, pp. 234, 240. 



