320 SUMMARY OF CURRENT RESEARCHES RELATING TO 



New Lejeunea from Bermuda and the West Indies. — Alexander 

 W. Evans {Bull. Torrey Bot. Club, 1917, 44, 525-28, 1 pL). The 

 author describes Lejeunea minuHloha, a new hepatic species which is 

 not uncommon in the West Indies. He discusses briefly its morphology 

 and structure. A. 6. 



Archegonium of Sphagnum squarrosum. — E. Melin {SvensTc Bot^ 

 TidsJcr., 1910, 10, 289-311, G figs. See also Bot. Centmlbl., 1917, 

 135, 331-332). The author writes on the archegonia of Sphagnum 

 squarrosum, and states that archegonia are not at all uncommon in 

 Sphagnum, especially in the dioecious species, though sporogonia are 

 rather rare. In S. squarrosum archegonia were very common in the 

 years 1911-1913. The material examined came from Nocby, near 

 Upsala in Sweden. The number of archegonia in a fertile shoot varies 

 according to the species, the coarser species having generally more and 

 the delicate ones less. Growth begins in August and takes place by 

 means of a two-edged apical cell, which cuts off segments on each side, 

 thereby forming the massive foot of the archegonium. So soon as 

 about seven segments have been formed, division takes place in these 

 in the manner characteristic of all moss archegonia, which is here 

 described in detail. As regards development the Sphagnum archegonium 

 holds a position between that of mosses and liverworts. The number of 

 canal-cells varies, according to the species, from ten to twenty. Specially 

 interesting is the behaviour of the central cell, which divides into such 

 similar cells that the author designates them both egg-cells, as well as 

 their daughter-cells when they divide. Immediately before fertilization 

 one of the egg-cells degenerates (not always the same one), which points 

 to the equal physiological value of both cells. The further process of 

 fertihzation could not be followed. The position of the ventral canal- 

 cell as a reduced egg-cell is established. E. S. Gr. 



Collection, Taxonomy, and Ecology of the Sphagna. — J. A. 

 Wheldon {Lancashire and Cheshire NaturaUst, 1917, 10, 233-6, 

 253-60 ; 1918, 10, 302-6, 319-24). The author gives hints as to the 

 collection and preservation of specimens, discusses the diverse systems- 

 of classification of the species and the distinguishing characters adopted 

 by various authors, and the variability of the plants in response to 

 environmental conditions. The rest of the paper is devoted to the 

 ecology of Sphagnum under the headings— moisture, climate, altitude, 

 light, soil, competition and dissemination. A. G. 



Moss Exchange Club. — W. Ingham (22,rd Annual Report, YorJcy 

 1918, 201-81). A list of the mosses and hepatics gathered by and 

 distributed among the members of the club, with critical notes by the 

 referees upon many of the specimens. In an appendix are given a 

 number of corrections and additions to the " Synopsis of the European 

 Sphagna " recently issued by the Club. A. G. 



Rhacomitrium in North America. — T. C. Frye {Brgoloqist, 1917, 

 20,91-98; 1918, 21, 1-lG). An account of the Rhacomitriums of 

 Western North America, with clear descriptions of the fourteen species. 



