Table 3.

Cardinal temperatures for germination for seven Euphorbia species exposed to a constant temperature regime (T _b: base temperature; T _c: ceiling temperature; T _o: optimal temperature), together with thermal times to germination for the 10th (Θ₁₀), 30th (Θ₃₀), and 50th (Θ₅₀) percentile for the germinated fraction (SE: standard errors)

Species	Light–storage	T b	SE	T c	SE	T o	SE	Θ10	SE	Θ30	SE	Θ50	SE
E. bivonae	D–SS	7.8	0.22	26.1	0.17	17.0	0.12	34.3	1.53	36.3	1.67	41.7	2.11
	D–LS	7.6	0.52	32.4	0.51	20.0	0.28	29.1	2.29	30.9	2.51	33.8	2.88
	L/D–SS	8.4	0.16	26.4	0.15	17.4	0.09	42.1	1.55	48.6	1.95	54.1	2.36
	L/D–LS	9.0	0.96	31.7	1.08	20.3	0.62	23.7	4.56	25.9	5.25	28.5	6.17
E. ceratocarpa	D–SS	8.8	0.18	27.6	0.24	18.2	0.12	43.3	2.03	43.7	2.05	44.9	2.14
	D–LS	8.5	0.65	30.7	0.57	19.6	0.38	25.3	3.03	28.4	3.67	31.6	4.44
	L/D–SS	9.2	0.13	27.5	0.19	18.4	0.10	41.4	1.50	42.5	1.56	44.5	1.68
	L/D–LS	9.5	0.37	31.2	0.42	20.4	0.25	27.2	2.10	33.9	3.07	38.0	3.76
E. characias	D–SS	7.6	0.17	21.1	0.11	14.3	0.08	23.0	0.96	24.0	1.02	31.7	1.53
	D–LS	5.6	1.09	33.7	0.98	19.6	0.49	50.1	6.03	55.3	6.89	57.6	7.37
	L/D–SS	−0.5	3.98	34.3	1.79	16.9	1.47	91.2	19.49	91.9	19.66	99.9	22.0
	L/D–LS	6.8	0.41	32.7	0.37	19.7	0.21	47.1	2.56	49.3	2.75	53.7	3.13
E. dendroides	D–SS	9.1	0.47	30.6	0.45	19.9	0.29	22.6	2.07	28.0	2.97	33.1	4.08
	D–LS	7.9	0.51	34.7	0.77	21.3	0.35	26.8	2.10	29.6	2.50	32.3	2.88
	L/D–SS	8.7	0.15	28.7	0.25	18.7	0.12	23.2	0.80	26.9	1.01	31.3	1.29
	L/D–LS	7.9	0.34	33.4	0.42	20.6	0.20	27.0	1.44	29.5	1.65	31.8	1.91
E. melapetala	D–SS	8.9	0.18	23.6	0.39	16.3	0.18	18.8	1.23	21.3	1.53	28.3	2.24
	D–LS	11.1	1.15	30.2	0.51	20.6	0.56	18.9	3.10	19.1	3.19	19.5	3.31
	L/D–SS	4.2	0.86	25.2	0.27	14.7	0.41	61.5	5.19	61.5	5.19	65.1	5.71
	L/D–LS	10.6	0.75	30.1	0.30	20.4	0.36	19.8	1.86	21.0	2.03	22.6	2.30
E. myrsinites	D–SS	12.4	0.10	27.5	0.10	20.0	0.04	19.1	0.44	19.1	0.44	21.4	0.51
	D–LS	12.1	0.01	25.6	0.00	18.9	0.00	24.6	0.04	24.6	0.04	24.7	0.04
	L/D–SS	13.0	0.36	26.8	0.33	19.9	0.18	17.6	1.82	18.1	1.89	20.8	2.29
	L/D–LS	11.6	0.40	30.2	0.20	20.9	0.20	30.8	1.98	31.2	2.02	31.2	2.02
E. rigida	D–SS	6.2	0.57	27.1	0.40	16.6	0.04	25.5	2.05	28.4	2.36	29.8	2.56
	D–LS	7.0	0.51	31.1	0.37	19.1	0.00	32.2	2.28	34.8	2.60	38.7	3.08
	L/D–SS	6.7	0.81	27.2	0.64	16.9	0.18	24.1	3.10	25.7	3.40	27.7	3.80
	L/D–LS	7.6	0.69	32.6	0.71	20.1	0.20	30.2	3.19	32.3	3.55	35.4	4.07

No germinations were observed at constant temperature for Euphorbia amygdaloides subsp. arbuscula.

Abbreviations: D, complete darkness; L/D, light/darkness (12/12 hr photoperiod); LS, long storage; SS, short storage.