1. Fronds erect, all pinnae ascending (45–60º); ultimate segments obtuse; plants usually growing as clusters of multiple crowns [petioles with brown outer hairs and white undercoat of varying thickness, leaf axes with cleanly abraded indument of reddish brown contorted hairs; young fronds bright green]. … L. revoluta
1. Fronds arching, only distal pinnae ascending (ca. 60º), proximal ones patent or reflexed; ultimate segments acute; plants usually growing with one main crown, smaller lateral crowns may occur after injury or with age [leaf axes with hairs either paler or at least on rhizomes and lower petioles spreading; young fronds usually in a copper-tone (cuprous) colour]. … 2.
2. Setiform hairs on rhizomes and petioles dark brown to blackish, 1-3 mm long; fertile fronds usually less than 1.75 m long; paraphyses shorter than sporangia. … L. quesadae
2. Setiform hairs on the petioles ferruginous to golden, 0.5 to several cm long; fertile fronds commonly reaching 2–5 m; paraphyses longer than or of the same length as sporangia. … 3.
3. Segment margins weakly to strongly revolute, rhizomes and petioles with one type of pluricellular hair, forming a soft, woolly indument, outer layers shiny golden, inner layers pure white, easily abraded, leaving the epidermis smooth [similar indument on rhachises and costae usually more plastered and less shiny than on petioles; laminae abaxially grayish green, if glaucous or white then veins spared]. … L. christii
3. Segment margins flat or weakly revolute, rhizomes and petioles with two types of pluricellular hairs, the spreading setiform hairs ferrugineous to reddish brown (rarely partially blackish), undercoat of contorted white to brown catenate hairs usually only persistent at petiole bases [similar indument on rhachises and costae with both types of hairs but white, caduceus; laminae abaxially glaucous or white, usually covering the veins]. … 4.
4. Setiform hairs on petioles dark reddish brown, bristly, spreading, distal parts not or only weakly contorted, young rhachises and costae with short white hairs, all hairs leaving a scabrous surface when abraded; laminae abaxially usually white. [upper montane forests, usually above 2500 m] … L. quadripinnata forma “bilineata”
4. Setiform hairs on petioles ferrugineous (orange-brown), relatively soft, basal parts spreading, distal parts often matted, young rhachises and costae with similar indument as petioles, hairs leaving a smooth surface except for scabrous petiole bases; laminae abaxially often bluish but intensity variable depending on age and external factors. [upper and lower montane forests, also below 2000 m] …. L. quadripinnata forma “caesia"