Table 1.

Morphological variation in seed and pollen characters of Erdtmanithecales, Ephedrispermum and Ephedra

	Erdtmanithecales	Ephedrispermum lusitanicum	Ephedra portugallica	Ephedra drewriensis	Extant Ephedra*
Length/width of pollen grains	approx. 15–20 µm/11–12 µm	approx. 23 µm/10 µm	approx. 33–40 µm/20–25 µm	approx. 50 µm/20 µm	(25–)30–70(–80) µm/(16–)20–40(–50) µm
Inferred total no. of ridges on pollen grains†	3	<12 (?)	20–30	12–14	Variable, 4–20
Discarded pollen exines found in situ	No	No	Yes	Yes	Yes‡
Seed length (mm)	1·0–1·2	0·6–0·9	0·8–1·2	1·2–1·4	6–7 or more
No. of angles on seed envelope	3	4	4	4	2-, 3-, 4-angled or globulose
Seed form	Ovoid	Spherical	Ovoid	Ellipsoid	Variable§
Papillae on seed envelope	No	No (?)	Yes	Yes	Yes
Orientation of outermost sclerenchymatic cells	Isodiametric	Transverse	Longitudinal	Longitudinal	Longitudinal
Length of sclerenchymatic cells	10 µm	c. 30 µm	10–30 µm	Up to 70 µm	Variable¶, 50–200 µm

^* Note that we do not cover the morphological variation of all extant species here.

^† Generally, the total number of ridges cannot be observed in fossil grains, but is inferred from the number of visible ridges on the exposed side of the grain.

^‡ See El-Ghazaly et al. (1998).

^§ Often ovoid, but sometimes ellipsoid or globulose.

^¶ Nine species from all the major clades were investigated: Ephedra alata C-311 (S), E. altissima C-635 (S), E. antisyphilitica C-610 (S), E. californica C-598 (S), E. distachya C-535 (S), E. equisetina C-461 (S), E. frustillata 03–1721 (S), E. intermedia C-326 (S), E. likiangensis 03–926 (S).