| 1 | Branch-segments 3-8 ribbed; stem-spination well developed; pericarpel and fruits spiny or at least with bristles |
| 1' | Branch-segments flattened; stem-spination usually inconspicuously developed; pericarpel and fruits naked |
| 2 | Flowers orange |
| 2' | Flowers white |
| 3 | Flowers large, ca. 4 cm in diameter, intensely orange, shimmering, pericarpel with prominent, long, dark spines |
| 3' | Flowers smaller, ca. 2 cm in diameter, waxy-orange, pericarpel naked or with few bristles |
| 4 | Flowers intensely red-magenta to orange |
| 4' | Flowers yellowish, whitish or cream, not intensely red |
| 5 | Stem pendulous, spines absent or weak; mature fruit globose, pale pinkish to whitish |
| 5' | Stem erect at first, spines developed; mature fruit depressed-globose, angled, olive-brown |
