1.	Basal leaves pinnatifid to pinnatipartite	2
1.	Basal leaves entire to shallowly lobed	7
2.	Leaf lobes narrow and long (length/width ratio > 3), with acute tips	3
2.	Leaf lobes wide and short (length/width ratio ≤ 3), with rounded tips	5
3.	Whole plant arachnoid, basal leaves widened at the apex	S. aknoulensis
3.	Whole plant glabrous to sparsely arachnoid, basal leaves not or slightly widened at the apex	4
4.	Leaves coarsely divided, lobes 3–5 mm wide or more	S. squalidus
4.	Leaves finely divided, lobes 1–3 mm wide	S. siculus
5.	Basal leaves lyrate, with apex at least twice as wide as the lateral lobes	S. balansae
5.	Basal leaves not lyrate, with narrow apex, slightly wider than the lateral lobes	6
6.	Plant glandular; leaves lobed, with crenate margin	S. duriaei
6.	Plant eglandular; leaves deeply laciniate, with toothed margin	S. rupestris
7.	Leaves thick and rigid	8
7.	Leaves thin and soft	9
8.	Leaves with short and acute lobes	S. ×glaber
8.	Leaves with entire to dissected margins	S. aethnensis
9.	Basal leaves not or slightly widened at the apex	S. calabrus
9.	Basal leaves widened at the apex	S. sardous