Table 1. Key to extant and fossil species in Ephedra and other ephedroids.

1. Female cones lacking supporting bracts ------------------------------Siphonospermum [22]

–. Female cones bearing supporting bracts---------------------------------------------------------2

2. Female cones bearing multiple pairs/whorls of fertile bracts------------------Liaoxia [21]

–. Female cones bearing 1 pair/whorl of fertile bracts--------------------------------------------3

3. Female cones surrounded by furcated appendages-------------------------Gurvanella [27]

–. Female cones lacking furcated appendages------------------------------------------------------4

4. Cone bracts spine-like and lanceolate-----------------------------------------Beipiaoa [33], [54]

–. Cone bracts obtuse or acute when present-------------------------------------------------------5

5. Female cones bearing only a pair/whorl of terminal, fertile bracts and 1—multiple pair/whorls of inferior sterile bracts---------------------------------------------extant Ephedra [44]

–. Female cones having only a whorl of terminal, fertile bracts and lacking or having only a pair/whorl of inferior sterile bracts-------------------------------------------------- fossil Ephedra 6

6. Female cones having only a pair of inferior sterile bracts, and seed surface bearing transverse ridges------------------------------------------------------E. archaeorhytidosperma [17]

–. Female cones lacking inferior sterile bracts, and seed surface smooth--------------------7

7. Biovulate, and micropylar tube less than 0.8 mm-----------------------------E. hongtaoi [19]

–. Triovulate, and micropylar tube longer than 1 mm------------------E. carnosa [this paper]