Table 3.

Results of constraining trees

Constraint	Additional steps
(carbonaria, nigra)	11**
(denticulata, nigra)	17***
[(carbonaria, chilensis, denticulata), nigra)]	7*

Results are shown for constraining trees to have the indicated species as the sister taxon to G. nigra or having the three species form a trichotomy. The number of extra steps compared to the MP tree with G. chilensis as the sister to G. nigra is given. *, P < 0.05; **, P < 0.025; ***, P < 0.005 for Templeton’s (23) tests, indicating the MP tree is siginficantly better than any of the alternatives.