PREFACE. V s 



THIS account of the British Charophyta will be 

 completed in two volumes. The present volume 

 embraces the NITELLEJE (Nitella and Tolypella), 

 the second will include the OHARE^E (Nitellopsis, 

 Lamprothamnium and Char a). 



The systematic portion is preceded by an intro- 

 ductory chapter dealing with the growth and structure 

 of the Charophyta generally, their distribution, affini- 

 ties, etc. For the facts concerning their cytology 

 and minute histology we have had to depend largely 

 on the writings of others, having ourselves had little 

 opportunity for such studies. Many separate papers 

 have been published on these branches of the subject, 

 especially by Continental botanists, and students 

 wishing for further information thereon will find full 

 references to such papers in the bibliography to be 

 included in the second volume. 



The plates illustrating the species included in this 

 volume are almost all from the pencil of Miss Mary 

 Groves, to whom we are much indebted for this im- 

 portant contribution to the work ; twelve are now 

 published for the first time ; four have already 

 appeared in the * Journal of Botany ' ; among the 

 latter is the beautiful illustration of Nitella hyalina, 

 the work of the late Henry Groves ; the two plates 

 relating to structure, taken respectively from the 

 works of De Bary and Pringsheim, and the text- 

 figures, which have been gleaned from various sources, 

 have been kindly copied for us by Miss Gr. M. Towsey. 

 For permission to reproduce Strasburger's figure on 



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