Table 1.

Linear mixed effect models showing T. porrifolius and T. pratensis compared with the hybrid taxon. Number of tertiary stems and number of buds per plant were square-root transformed. d.f., degrees of freedom.

Response variable	Species	Value	Standard error	d.f.	t-value	P-value
Root length	(Intercept)	17.691	1.375	171	12.862	<0.0001
	T. porrifolius	−2.362	1.448	171	−1.632	0.1046
	T. pratensis	−3.886	1.600	171	−2.429	0.0162
Root width at top	(Intercept)	8.432	1.906	177	4.424	<0.0001
	T. porrifolius	3.004	0.765	177	3.927	0.0001
	T. pratensis	0.479	0.827	177	0.580	0.5627
Mid-root width	(Intercept)	4.448	0.924	171	4.813	<0.0001
	T. porrifolius	2.185	0.514	171	4.249	<0.0001
	T. pratensis	−0.146	0.550	171	−0.265	0.7911
Root base-first node	(Intercept)	18.754	2.299	180	8.157	<0.0001
	T. porrifolius	−6.897	1.933	180	−3.568	0.0005
	T. pratensis	−5.535	2.156	180	−2.567	0.0111
Root base-shoot tip	(Intercept)	88.747	7.835	180	11.327	<0.0001
	T. porrifolius	−14.314	3.553	180	−4.028	<0.0001
	T. pratensis	−23.504	3.889	180	−6.043	<0.0001
Secondary stems	(Intercept)	4.467	0.571	180	7.821	<0.0001
	T. porrifolius	−0.362	0.561	180	−0.645	0.5195
	T. pratensis	−1.454	0.633	180	−2.295	0.0229
sqrt(Tertiary stems)	(Intercept)	1.365	0.257	180	5.315	<0.0001
	T. porrifolius	−0.332	0.225	180	−1.477	0.1416
	T. pratensis	−0.261	0.251	180	−1.036	0.3015
sqrt(Buds/plant)	(Intercept)	1.332	0.071	180	18.692	<0.0001
	T. porrifolius	−0.625	0.120	180	−5.194	<0.0001
	T. pratensis	−0.870	0.156	180	−5.583	<0.0001
Inflorescences/plant	(Intercept)	1.696	0.155	180	10.910	<0.0001
	T. porrifolius	−0.660	0.263	180	−2.512	0.0129
	T. pratensis	−0.141	0.340	180	−0.414	0.6797
All nine morphometric	(Intercept)	68889155	15339444	172	4.491	<0.0001
variables	T. porrifolius	−62878560	26130961	172	−2.406	0.0172
	T. pratensis	−65969696	32872942	172	−2.007	0.0463