Table 1. Actinorhizal nitrogen-fixing lineages identified in this study, with recommendations for comparative studies of closely related non nitrogen-fixing taxa.

Actinorhizal lineages	Clear sister for comparative work?	Bootstrap values
1–Myrica + Comptonia	Canacomyrica	100%
2–Casuarinaceae	Ticodendraceae + Betulaceae	100%
3–Alnus	Remaining Betulaceae	100%
4–Coriaria	Corynocarpus	100%
5–Datisca	Tetramelaceae	<50%
6–Dryadoideae	Rosoideae	70%
7–Elaeagnaceae	Barbeya	<50%
8–Colletieae	Granitites + Alphitonia	<50%
9–Ceanothus	Pomaderreae	63%

The lineage numbers correspond to those in Fig. 1.