Fig. 2.

Frequency distribution of seed set (A) after hand self-pollination in four categories, and (B) after cross-pollination in seven categories. The values of seed set for each category are grouped into increments of seed of 0·09 units ranging from 0 to 0·39 for seeds sired from self-pollination and from 0 to 0·59 for seeds sired from cross-pollination. The percentage of plants observed in the different categories of seed set was plotted within each SI category (see Fig. 1 for definitions of categories). Data were gathered for Flourensia cernua in the Mapimí Biosphere Reserve from a hand-pollination experiment (self- and cross-pollination), involving 50 plants from low-density scrubs and 50 plants from high-density scrubs. Plus and minus signs are presented for the Haberman standardized residual analyses: + or – sign over a column indicates a significant excess or deficit of plants in that category, respectively.