A Biosystematic Study of Microseris Subgenus Monermos (Compositae: Cichorieae)

The taxonomy of Microseris subgenus Monermos (Hook. f.) Chambers (Compositae) is investigated. Two species are recognized, namely M. scapigera (sol. ex A. Cunn.) Sch.-Bip. and M. lanceolata (Walp.) Sch.-Bip., which are confined to New Zealand and Australia respectively. In M. scapigera, taxonomic subdivision was not practicable, the formae of Allan (1961) not being upheld. Microseris lanceolata is subdivided into three groups which are described informally as races. The races are viewed as probable subspecies but need further study before this status can be confirmed. The two species are described and illustrated and details are given for each on typification, synonymy, chromosome number, distribution, ecology and geographical variation. Strong self-incompatibility is prevalent in both M. scapigera and M. lanceolata. The only exceptions in the populations examined were in M. scapigera, in which two populations were only moderately self incompatible, and another was substantially self-compatible. The last population appeared to have morphological and behavioural adaptations to promote autogamy. Artificial hybridizations were made within and between the two species. Microseris scapigera and M. lanceolata were freely or poorly intercrossable according to the populations used, and formed semi-fertile or sterile hybrids. Semi-fertile hybrids were virtually blocked from forming a F2 generation (fruit set was very low and no fruits germinated) but they cold be backcrossed. Fertility in BC1 hybrids was mostly higher than in the F1, but was not restored to normal. Microseris scapigera and M. lanceolata race 1 appear to have largely homologous chromosomes. Attempts to cross the species of subgenus Monermos with M. borealis (subgenus Apargidium) were unsuccessful