| 1 | Bracteoles very small, 2-5 mm long, less than half the length of the calyx |
| 1' | Bracteoles more than 5 mm long, usually almost as long as the calyx or a little longer |
| 2 | Bracteoles linear-subulate, 10-15 x 1-3 mm |
| 2' | Bracteoles oblong, oblong-elliptic, oblong-obovate or rhomboid, 7-18 x 3-7 mm |
| 3 | Bracteoles thinly pilose, with hispid-ciliate margins; apex of calyx bearing 5 spreading, spinous awns 2.5-4 mm long |
| 3' | Bracteoles rather densely stellate-pubescent externally; apex of calyx with very short spines or cusps |
| 4 | Calyx-tube c. 20 mm long, apical cusps slender, inconspicuous; nutlets often pilose at apex |
| 4' | Calyx-tube 7-12 mm long, apical cusps rather rigid, spinous; nutlets glabrous or sparsely glandular-pilose at apex |
| 5 | Ratio leaf length/width 1.5-2.0; leaf apex rounded or very obtuse, broad; leaf indumentum whitish or greyish tomentose, no or slight contrast between both tomentose sides |
| 5' | Ratio leaf length/width 2.1-3-9; leaf tapering to a narrow, obtuse or subacute apex; leaf indumentum often yellowish tomentose, strong contrast between lower side and darker upper side |
