VoMMi: VIII JUNE, 101 !» No. 3 



SEX SEGREGATION IN THE HRYOPHYTA. 



By E. J. COLLINS. B.A. ( amb., B.Sc. L«.iul. 

 Botanist to the John Innes Horticultural Institution. 



(With Pluto VI and Five Text-figures.) 



Whilst the majority of plants show an alternation of generatiorm 

 in the complete life cycle, it is in the Bryophyta alone that the gamcto- 

 phytic {n) phjvse shows an independent growth combined with a high 

 degree of morj)hological differentiation. The study of sex in this group 

 does not involve, as it does in the highest forms of plant life, the con- 

 sideration of sporophy tic tissues differentiated as "sex organs" in respcjnse 

 to the parasitic nature of the gametophyte generation. It may well be 

 that very considerable light would be thrown on the nature of sex and 

 much information gained jis to its mode of inheritance by further studies 

 among the lower plant groups. 



In recent years no more interesting and suggestive pai)ei-s concerning 

 sex in Mosses have been published than those of El. and Em. MarchaP, 

 and a very brief outline of these papers will serve to show the scoj>e of 

 their researches. 



By compounding a suitable culture fluid, these investigators have 

 grown what might be regarded Jis pure line cultures of the various 

 mosses experimented with. Starting with the spores from capsules of 

 dioicous forms, these were shown to be uni-sexual, inasmuch as the 

 protonemata developed from them produced leafy axes which were all 

 of one sex, either male or female. The male and female axes so pro- 

 duced were approximately equal in number, and the protonemata ob- 

 tained vegetatively from them gave leafy axes of the s«iine sex as the 

 parent axes. Protonemata were then induced to develop aix)sixjr()usly 

 from sporophytic (2n) tissue, and these produced a prop<jrtion of herma- 

 phrodite axes. The projx)rtion of hermaphrodite axes however wjvs very 

 low; e.g. in Bryum caespiticium, of 1738 axes 1579 were* male, 154 



* J/«fifi. de Vacad. roy. de lielgique, HK)6 ; liitU. de Vacad. roij. de liehjique, Clause dc» 

 Sciences, 1907, 1909, 1911. 



Joam. of Gen. viii 10 



