2.3. Morphological and reproductive traits

Some morphological traits such as lengths of the main roots and floral stems as well as the leaf area were measured. Some plant samples (n = 6) subjected to analysis of some metabolites were freeze-dried to prevent potential degradation of the metabolites during dryness. Other plant samples (n = 8) were oven-dried for 48 h at 80 °C for potential measurement of total and fractional biomass. Each of the individuals was weighed to determine the total biomass (expressed as g individual⁻¹). All plant samples were separated into roots, leaves and reproductive organs. The biomasses of below-ground roots, leaves and reproductive organs were determined. The stem mass was not included in the measured criteria as C. glomerata was recorded as stemless (Boulos, 1995).

The reproductive traits per individual were assessed at the peak of the flowering stage, i.e., April 2017 and 2018, and fruiting stage, i.e., May 2017 and 2018. In the laboratory, the number of heads per individual was counted. The reproductive output was evaluated by counting the number of heads and fruits (achenes) per plant. We also weighed the heads (including peduncles and the flowers with their ancillary structures) after the drying process and the mass of seeds to estimate the mean seed mass.

To estimate the sexual reproductive effort, we calculated the relative reproductive allocation (RRA) (Dujardin et al., 2011) in order to evaluate changes in strategies of biomass allocation in the species under study among habitats (Bazzaz, 1996). RRA is defined by the equation: RRA = Sexual reproduction biomass/Vegetative biomass.