PREFACE ix 



so also to Mr. W. Lawrence Balls, of the Khedivial Agricultural 

 Society, Cairo, for having prepared for me an interesting collection 

 of the cottons at present being specially grown and hybridised in 

 Egypt. To Mr. Isaac Henry Burkill, my successor as Reporter 

 on Economic Products to the Government of India, I am also 

 under obligation, more especially for having sent me a complete 

 duplicate set of all the collections in the herbarium belonging to 

 that office, not a few of which had been procured by myself, and 

 which bore notes and descriptions which otherwise I might have 

 overlooked. 



Mr. John S. Slater, who for some time past has been giving 

 attention to the subject of pollen-grains, has investigated those met 

 with in an extensive series of species, varieties, and races of Qossy- 

 pium, furnished by me for that purpose. His results have been 

 dealt with very briefly, but it is believed the subject will be found 

 of considerable interest and value, in the light of a possible aid to 

 the study of hybrids generally and the hybridisation of the cottons 

 in particular. I am thus under no small obligation to Mr. Slater 

 for his kind collaboration. 



I am much indebted to my niece Miss L. Hall, for having 

 verified the references, and prepared under my instructions the 

 Appendix and Index. It will be found that the Appendix consists 

 of three lists : ' A ' an enumeration of the specimens examined 

 by me assorted in alphabetical sequence of the names of the 

 collectors ; ' B ' the bibliography of cotton an assortment of books, 

 reports, periodicals, in sequence of authors' names ; and ' C ' the 

 synonymy of the species of Gossypium. The Index, therefore, gives 

 the references to subjects not shown under ' A,' ' B,' and ' C ' of the 

 Appendix. 



To Messrs. Longmans, Green & Co., my thanks are in a special 

 degree due for not only having devoted the time and care necessary 

 for the publication of a more or less technical work, but for having 

 generously allowed me to illustrate it with the completeness that alone 

 can insure success. The illustrations are of four kinds : (a) repro- 

 ductions by the three-colour process of photography (half natural 

 size) ; (b) photographs of herbarium specimens, mostly the types of 

 the species concerned (the scale in each case being indicated) ; 



(c) original drawings made by Miss M. Smith, from dried specimens 

 (approximately life size, the dissections being usually enlarged) ; 



(d) micro-photographs of pollen-grains. Two of Miss Smith's 



