Fig. 1.

Piecewise regression analyses of paired endemic (filled circles, solid lines) and non-endemic (open circles, dashed lines) species representative of the whole range of variation recorded. (A) The endemic Fumana paradoxa and the non-endemic Helianthemum cinereum (Cistaceae) in Andalusia (pair 2). (B) The endemics Thymus orospedanus and Sideritis incana, and the non-endemic Teucrium polium (Lamiaceae) in Andalusia (pair 4). (C) The endemic Triteleia peduncularis and the non-endemic Zigadenus venenosus (Liliaceae) in California (pair 5). (D) The endemic Cienfuegosia yucatanensis and the non-endemic Sida acuta (Malvaceae) in Yucatan (pair 8). Dotted lines indicate when the number of pollen tubes equals the average number of ovules per flower. Taxa codes are as in Table 1. Note that scales were adjusted to data ranges.