1	Pinnae simple or pseudodichotomously branched; pinnules palmately lobed, not articulate		(2)
+	Pinnae 1- or 2-pinnate; pinnules simple, pinnately or irregularly lobed, articulate or not		(4)
2 (1)	Veins anastomosing.		1 L. merrillii
+	Veins free		(3)
3 (2)	Margin of pinnae entire, cartilaginous.		2 L. circinnatum
+	Margin of pinnae serrulate, not cartilaginous.		3 L. longifolium
4 (1)	Pinnules not articulate to rachis		(5)
+	Pinnules articulate at base or at base of stalks		(6)
5 (4)	Fertile pinnae and sterile pinnae monomorphic; pinnules 1-3 cm wide.		4 L. flexuosum
+	Fertile pinnae and sterile pinnae subdimorphic; pinnules 4-6 mm wide.		5 L. japonicum
6 (4)	Pinnules articulate at base of stalks; pinnae similar to L. flexuosum.		6 L. yunnanense
+	Pinnules articulate at base (articulation at top of stalks)		(7)
7 (6)	Pinnules small, often deltoid, obtuse at apex, 1.5-3 cm or rarely longer, herbaceous; rachis slender.		7 L. microphyllum
+	Pinnules broadly lanceolate, 8-12 cm or more, papery; rachis robust		(8)
8 (7)	Pinnae regularly 1-pinnate; rachis with dense brown long hairs; pinnules 9-13 pairs, truncate at base, not dilated.		8 L. polystachyum
+	Pinnae irregularly 1- or 2-pinnate; rachis glabrous; pinnules often 3-5 pairs, often cordate at base.		9 L. salicifolium