Dec. 1.8, 1 8 84] 



NA TURE 



151 



well-educated Norwegians (who all read English as a matter of 

 course). They cannot fail to be indignant if such unjust treat- 

 ment of a national work, which genuine Norwegians understand 

 and appreciate, is allowed to pass unrefuted. Beside c .viiieli, 

 Englishmen in search of available and reliable infor non con- 

 cerning Norway might be grossly misled. 



\V. MATTIEl \\ II L1AMS 



APOSPORY IN FERNS 



A PARAGRAPH in the report in Nature (p. 119) of 

 the meeting of the Linnean Society for November 20 

 last contained what is, to the best of my belief, the first pub- 

 lication of one of the most interesting botanical observa- 

 tions which has been made for some time. As it is quite 

 possible that this brief record may escape the notice of a 

 good many botanists, I venture to give the matter a little 

 more prominence. 



At the meeting referred to, Mr. E. T. Druery made a 

 second communication (the first did not, I think, receive 

 m\ record) upon a singular mode of reproduction in 

 Athyrium Filix-fwmina, var. clarissima. In this fern the 

 sporangia do not follow their ordinary course of develop- 

 ment, but, assuming a more vegetative character, develop 

 more or less well-defined prothallia, which, according to 

 Mr. Druery's observations, ultimately bear archegonia 

 and antheridia. From these adventitious prothallia the 

 production of seedling ferns of a new- generation has been 

 observed to take place in a perfectly normal way. 



Mr. Druery very kindly ottered at the meeting to supply 

 me with some of his material. This reached me on 

 Novemher 29, and I immediately placed it in the hands 

 of my friend Mr. F. O. Bower, who was engaged in other 

 research connected with the vascular cryptogams in the 

 Jodrell Laboratory of the Royal Gardens. Although in 

 the material sent me the abnormal development of the 

 sporangia had not proceeded very far, Mr. Bower obtained 

 evidence which, as far as it went, was entirely confirma- 

 tory of the correctness of Mr, Druery's observations. 

 With appropriate cultural treatment prothalliform bodies 

 have already made their appearance, but have not yet 

 reached the stage at which archegonia and antheridia are 

 developed. They are, however, furnished with root-hairs. 



This is, however, not all. Mr. Bower placed himself 

 in communication with Mr. Druery, and paid a visit to 

 his collection of ferns. By the kindness of this gentle- 

 man i . ed to bring away specimens of another 

 . hum angulare,v&r. fiulcherrima which alto- 

 gether eclipses the Athyrium, remarkable as that is. In 

 the Polystichum the apex of the pinnules grows out into 

 an irregular prothallium, upon which Mr. Bower with 

 little difficulty was able to demonstrate at Kew the exist- 

 ence of characteristic archegonia and antheridia. In this 

 case the production of the prothallium is not even asso- 

 ciated locally with the sporangia, but it appears as a direct 

 vegetative outgrowth of the normal spore-bearing plant. 

 Theoophore is a mere vegetative process of the sporo- 

 phore, a suppression of ti 1 in of the two genera- 

 h exceeds even that which obtains in the 

 flowering plant. 



Mr. Druery's discovery, for which I have borrowed 

 Mr. Bower's convenient term Apospory, is the direct 

 converse of the Apogamy in the fern, discovered by Prof. 

 Farlow. In this the sporophore is a vegetative outgrowth 

 from the oophore. The parallel phenomena in the life- 

 history of the moss have been known for some time. But 

 this point and all detailed observations at present available 

 will be dealt with in the communication which Mr. Bower 

 will make at the meeting of the Linnean Society this 

 (Thursday) evening. While every merit must be attributed 

 to Mr. Druerj for the firsl observations of this important 

 fact, he has with great liberality allowed Mr. Bower free 

 liberty to discuss the histological and theoretical points 

 involved. 



The obvious possibilities of discovery with regard to 

 the reproduction of ferns may now be regarded as ex- 

 hausted. It may be interesting to give the dates of the 

 different steps : — 



'597 Gerarde Observed seedling plants near parents* 



i ! ins , Sporangia. 



[669 ( die ... ..'. ... Spores. 



1686 Kay Hygroscopic movements of sporangia, 



1715 Morison Raised seedlings from spores. 



1788 Ehrhart Prothallium. 



17S9 Lindsay Germination of spoi 



1827 Kaulfuss Development of prothallium. 



1844 Nageli Antheridia. 



1840 Suminski Archegonia. 



1S74 Farlow Apogamy. 



1S84 Druery Apospory. 



Royal Gardens, Kew W. T. Thiselton Dyer 



MODERN ENGLISH MA THE MA TICS l 



VOU will remember that two years ago it was announced 

 * from this chair that the Council had settled the con- 

 ditions under which the De Morgan Medal should be 

 given, and that the first award would be made at the 

 anniversary meeting of 1884. 



I have now to make the announcement that the Council 

 has decided that the first medal should be given to Prof. 

 Cayley, in acknowledgment of his work in the theory of 

 invariants. 



As this is the first award of the medal, I may remind 

 you of its origin. Soon after the death of De Morgan, 

 some of his admirers started a subscription for the double 

 purpose of having a bust executed and founding a medal 

 to be given in his memory. The bust now adorns the 

 library of the London University, where also his valuable 

 collection of books is preserved. The medal was offered 

 to the Mathematical Society, and its Council accepted 

 the honourable duty of determining its award. There is 

 a peculiar fitness in the medal being thus connected with 

 our Society ; for this Society was founded with the active 

 co-operation of De Morgan by a number of his advanced 

 students, among whom his talented son George, who died 

 soon afterwards, took the lead. De Morgan himself was 

 the first President, and our /'■■, > begin with a very 



characteristic opening speech by him. 



The medal is to be given for eminent original work in 

 mathematics, and no more fitting memorial than this 

 could in my opinion be devised for a man who spent his 

 whole life in carefully preparing the foundation for such 

 work by his teaching and his writings. 



De Morgan was pre-eminently a teacher. His most 

 original work does not so much increase our stock of 

 mathematical knowledge, but is concerned with mathe- 

 matical reasoning, and with exact reasoning in general. 



In the opening speech referred to, De Morgan himself 

 divides exact science into two branches, the analysis of 

 the necessary laws of thought, and the analysis of the 

 try matter of thought. His own work belongs to 

 the former. He was a logician much more than a mathe- 

 matii ian in the ordinal) sense of the word, and when 

 reading his mathematical works I have always had the 

 that he studied mathematics not so much for its 

 own sake as on account of the logic contained and exem- 

 plified in it. I once made this remark in the Profe- 

 Common Room of University College, when an old col- 

 league of his turned round and said, " You are quite 

 right, he told me so himself." 



In this work De Morgan did not stand alone. We 

 may almost take him as a type of his period. It has 

 often struck me as a noteworthy fact that in England, 

 after the long pause in mathematical activity, the work 

 taken first in hand was investigation into the very bases 



1 An address delivered by Prof. Henrici, l'.RS,. al the annual meet- 



I .. ! . . : ' . 



I i.il Medal to Prof. Cayley, F.R.S. 



