Additional breeding experiments withSaxifraga

Summary

• 1. Comparative descriptions are given of British material ofSaxifraga rosacea, S, caespitosa, andS. hypnoides.

• 2. Families have been raised from selfings and from crossings of our stock plants of these taxa, and from reciprocal crosses ofS. hypnoides andS. granulata.

• 3. In the discussion it is shown that genetical sterility barriers are not important in keeping the taxa distinct and their absence or incompleteness explains the occurrence of ‘intermediates’ in certain wild populations and in some plants in cultivation.

• 4. The doubtful taxonomic value of the differences betweenS. caespitosa andS. rosacea is considered and the need for further comparative researches, especially on Welsh and Scottish populations, is suggested.