Table 2.

Fossils used for nine calibration nodes of the molecular clock. The four with dashes in the last three columns were not used because they are redundant with (and sometimes younger than) the ones used

Calibration node*	Fossil assigned to	Fossil (reference)	Location	Period	Age	OFFSET	LOGMEAN	LOGSTDV
21	All taxa	Calamostachys binneyana (Good, 1971)	USA, Kentucky, Lewis Creek and Shack Branch	Lower Pennsylvanean	323–359	323	3	1
22	All Equisetum	Equisetum thermale (Channing et al., 2011)	Argentina, Patagonia	Middle to Upper Jurassic	152–164	–	–	–
22	All Equisetum	Equisetites lyelii (Watson, 1983)	UK, Sussex	Lower Cretaceous	125–150	–	–	–
22	Subgenus Paramochaete	Equisetites minimus (Falaschi et al., 2009)	Argentina, Sta Cruz Prov.	Middle Jurassic	174–164	164	2	1
22	Subgenus Paramochaete	Equisetum laterale (Gould, 1968)	Australia, Queensland	Middle Jurassic	145–174	–	–	–
25	E. palustre, E. pratense	Equisetum ‘pratense’ (Zhang et al., 2007)	China, Yunnan	Late Tertiary, Miocene	5.3–23	5.3	0.5	1
27	E. telmateia, E. braunii	Equisetum maximum (Reed, 1971)	Upper Silesia (Poland)	Miocene	5–23	5	0.5	1
28	E. sylvaticum, E. diffusum, E. arvense, E. fluviatile	Equisetum fluviatoides (McIver and Basinger, 1989)	Canada, Saskatchewan	Palaeocene	56–66	56	1	1
31	Subgenus Hippochaete	Equisetum perlaevigatum (Reed 1971)	USA, Colorado	Late Cretaceous	66–72	66	1	1
32	E. variegatum, E. ramosissimum, E. praealtum, E. hyemale, E. giganteum, E. xylochaetum, E. laevigatum, E. myriochaetum	Equisetum clarnoi (Brown, 1975)	USA, Oregon	Middle Eocene	37.8–47.8	37.8	1	1
34	E. giganteum, E. xylochaetum, E. laevigatum, E. myriochaetum	Equisetum sp. (Thomasson, 1980)	USA, Nebraska	Late Tertiary	0–5.3	–	–	–
34	E. giganteum, E. xylochaetum, E. laevigatum, E. myriochaetum	Equisetites sp. (Contreras and Lutz, 2014)	Argentina, Formosa, Bermejo River	Lower Holocene	2.6–11.6	2.6	0.5	1
38	E. praealtum, E. hyemale	Equisetum hyemale (Reed, 1971)	Hungary	Upper Miocene	11.6–13.8	11.6	0.5	1

*Numbers correspond to nodes shown in Fig. 2