A BIOSYSTEMATIC STUDY OF SOME GLYCERIA SPECIES IN BRITAIN ^ 



2. Cytology 



/• 



By Martin Borrill 



Welsh Plant Breeding Station, Aherystwythf 



Introduction 



An investigation of chromosome pairing at meiosis in the British species of Section 

 Glyceria was undertaken in order to study the relationships of the species. 



Previous cytological studies in this group were confined to somatic chromosome counts 

 in the root-tips, and the findings of these authors are summarised in the section of this 

 paper deaHng with chromosome numbers. G. X pedicellata has been counted only once 

 before, by Fitzpatrick in 1946. 



Material 



In the species of Section Glyceria many small local populations occur, often 

 distinguished by minor morphological characteristics, and fixations were made from some 

 of these in order to see whether they were chromosomal races. The sources of these 

 populations are listed in Table 1 ; herbarium specimens of representative plants were 

 prepared and citations are given in the following abbreviated form : — e.g. H.403 = 

 specimen No. 54403 in the Herbarium at the University College of Leicester. The race 

 references in the table indicate that the population concerned was sampled for seed, and 

 subsequently compared in an experimental garden trial, the results of which will form 

 part of a further paper. 



Table 1 . 



Source of plants used for chromosome counts. 



Herb. 



Race 



Plants 



Location 



Vice-county 



Habitat 



No. 





counted 



G. 



declinata 





403 





5 



Botcheston Pond 



Leicester 



Shallow water in mud 



413 



C 



8 



Ulverscroft 



Leicester 



Gravel bed of stream 



427 



D 



4 



Cadgwith 



West Cornwall 



Quarry pond at cliff top 



436 





3 



Grimley Pond 



Worcester 



Water-logged mud 



443 





1 



Narborough ' bog ' 



Leicester 



Trampled mud 



446 





3 



Ashtead Woods 



Surrey* 





448 





5 



Roecliffe 



Leicester 



Swampy place in field 



450 





1 



Roecliffe 



Leicester 



Stony stream bed 



458 





2 



Malham 



Mid West York 



Tarnsidc near Gt. Close 

 Mire 



464 



B 



7 



Malham 



Mid West York 



Foot of limestone cliff 



468 



A 



4 



Malham Beck 



Mid West York 



Mud bank in limestone 

 stream 



473 





2 



Malham Beck 



Mid West York 



Small rivulet 



506 



E 



6 



Hopedale 



Stafford 



Muddy pond rich in humus 



507 



Total 



5 

 56 



Esher Common 



Surrey* 





t Part of a thesis for the degree of Ph.D. of the University of London. 



t The experimental work for this investigation was carried out in the Botany Department at the University College of Leicester. 

 * Plants raised from seed supplied by Dr. J. M. Lambert 



299 



