WATER RELATIONS OF SPECIES: COMPARISONS 291 



ber of plants per container was 7 for F. vulgaris; 36 for S. hypnoides; 4 for 

 T. sangiiinea; and 4 for P. padns. The containers were not replicated. 

 Results. Results for the four species are presented in Tables i(a)-(d). 



Considering first the herbaceous species, it is apparent that growth of 

 S. Jiypnoides was significantly reduced in moisture regime I as compared 

 with O ; and also in II as compared with I. In contrast, the differences in 

 growth of F. vulgaris in the same moisture regimes were not significant. 

 The significance of the differences between treatments was decreased by the 

 presence of one or two exceptionally small plants in each container. For all 

 species, to ensure that the soil would be fully exploited by roots, it was 

 necessary to have the plants rather close together; and it is possible that 

 inter-plant competition caused an increase in the between-plant variation 

 within each treatment. Notwithstanding, it is apparent that the growth rate 

 of 5. hypnoides was depressed to a larger extent in moisture regimes I and 



Table i 



Growth of four species in a limestone soil under three soil moisture regimes : O, soil 

 which was watered sufficiently often to prevent the development of measurable soil 

 moisture tension (SMT) (i.e., o-i to 0-2 atm) ; I, soil watered after drying-out to i atm 

 SMT ; II, soil watered after drying-out to 2 atm SMT. LSD = least significant difference 



('P'=o-05). n.s.=: not significant 

 (a) Filipeudida vulgaris 



Differences between treatments not significant, 

 (b) Saxifraga hypnoides 



