252 



J. K. MORTON 



Acknowledgments 



I would like to express my appreciation of the advice and assistance afforded to me 

 by Mr. R. A. Graham. In particular his assistance in obtaining many rare and interesting 

 mints has greatly facilitated this work. Also my thanks are due to Professor M. Thomas, 

 F.R.S. and Dr. K. B. Blackburn of the Department of Botany, King's College, University 

 of Durham, for their interest during the course of this work and for affording the facilities 

 under which most of it was carried out. 



Summary 



The chromosome numbers of British species and hybrids of the genus Mentha have 

 been determined from root-tip preparations and are summarised in the accompanying 

 table. In addition material from several Continental sources has been examined. The 

 status of these mints and the parentage of the hybrids are discussed. 



The mints contain two euploid series, the section Pulegium having diploid numbers 

 of from 10 to 40 and a base number of 5, and the section Mentha with diploid 

 numbers of from 24 to 132 and a base number of 6. Many of these numbers have arisen 

 *by allopolyploidy, but autopolyploid races occur in several of the species. The pro- 

 duction of functional diploid gametes and the occurrence of amphidiploidy in several 

 of the hybrids are noted. Vegetative reproduction plays an important part in the propagation 

 both of the species and of the hybrids in this genus. 



REFERENCES 



BAKER, J. G.. 1865, On the English mints, /. Bot. 3, 233-256. 

 BRIQUET, J., 1891, Labie^s Alpes Maritimes, 18-97. 



DARLINGTON, C. D. & JANAKI AMMAL, 1945, Chromosome atlas of cultivated plants. London. 

 DRUCE, G. C., 1928, British plant list, ed. 2. 



ERASER, J., 1927, Menthae Britannicae, Rep. Bot. Soc. & E.C., 8, 213-247. 

 GRAHAM, R. A., 1948, Mint Notes I, Watsonia, 1. 88-90. 



, 1950, Mint Notes, II, Watsonia, 1, 276-278. 



, 1951, Mint Notes, IV, Watsonia, 2, 30-35. 



, 1954, Mint Notes, V, Watsonia, 3, pt. 2, 109-121. 



LOVE, a. & D., 1948, Chromosome numbers of northern plant species, Dep. Agric. Rep. Series B, no. 3, 

 Rejkjavik. 



MAUDE, P. P., 1939, The Merton Catalogue, New Phyt., 38. 



SMITH, J. E., 1800, Observations on the British species of Mentha. Trans. Linn. Soc, London, 5, 171-217. 

 SOLE, W., 1798, Menthae Britannicae. 



TISCHLER, G., 1938, Pflanzliche Chromosomenzahlen, IV, Tabulae Biologicae, 16, 3. 

 WARBURG, E. F., 1952, in Clapham, A. R„ Tutin, T. G. & Warburg, E. F., Flora of the British Isles. 

 Cambridge. 



