KEY TO THE VARIETIES

1Plants usually (always?) with simply pinnate sterile leaves beside the fertile ones; fertile leaves simply pinnate; or, if bipinnate, at least some pinnules at the base of the terminal pinna, above the uppermost pinnate pinnae, suborbicular; the lamina not gradually passing from the bipinnate condition at base to the simply pinnate apex but with a rather abrupt transition.
1'Sterile simply pinnate leaves mostly wanting; no pinnules suborbicular; larger laminas upward gradually of simpler structure, with a gradual transition from the bipinnate base to the simply pinnate apex