Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
1 Leaves bipinnate- pinnatifid to tripinnate- pinnatifid (or to quadripinnate in the lower pinnae), divided 2.5-4×; [“ clade II”]. |
2 Leaves evergreen, the blades appearing more-or-less parallel-sided and minutely glandular- pubescent, especially on the indusium, rachis, and pinnae midribs; first basal-pointed pinnule of the basal pinna shorter than or equal to the next outermost basal-pointed pinnule; first basal-pointed pinnule of the basal pinna usually < 2× as long as the first tip-pointed pinnule of the basal pinna |
2 Leaves deciduous, the blades appearing more or less triangular and lacking gland-tipped hairs (except occasionally on the indusium); first basal-pointed pinnule of the basal pinna longer than the next outermost basal-pointed pinnule; first basal-pointed pinnule of the basal pinna > 2× as long as the first tip-pointed pinnule of the basal pinna. |
3 Leaf blade ca. 1× as long as the petiole; indusium occasionally glandular; first basal-pointed pinnule of the basal pinna 2.5-5× as long as the first tip-pointed pinnule of the basal pinna |
3 Leaf blade 2× as long as the petiole; indusium glabrous; first basal-pointed pinnule of the basal pinna ca. 2× as long as the first tip-pointed pinnule of the basal pinna |
1 Leaves pinnate, pinnate- pinnatifid, to bipinnate (or to bipinnate- pinnatifid in the lower pinnae), divided 1-2.5×. |
4 Leaves pinnate, divided 1× (the pinnae toothed, but not further lobed or divided); rachis densely clothed with blackish scales; [" clade I"] |
4 Leaves pinnate- pinnatifid to bipinnate (or to bipinnate- pinnatifid in the lower pinnae), divided 1.5-2.5×; rachis sparsely to moderately clothed with light tan to brown scales. |
|
5 Sori medial or submedial (some blade tissue visible on the underside of the blade between the sori and the margins); leaves evergreen or deciduous, dark- to bright-green, thin to stiff in texture. |
6 Scales of the petiole, rachis, and costae of 2 distinctly different types (broad vs. hairlike); leaves with 20-30 pairs of leaflets; [PA northwards]; [“ clade I”] |
6 Scales of the petiole, rachis, and costae broad, variable in size, but lacking scales of a hairlike type; leaves with 10-25 pairs of leaflets; [collectively widespread]. |
7 Leaves dimorphic, the deciduous, fertile leaves erect, 2-3× as long as the spreading, evergreen, sterile leaves, which form a winter " rosette"; fertile leaves linear- lanceolate in outline, generally 4-8× as long as wide; pinnae mostly 1.5-3× as long as wide, triangular; scales at base of petiole tan; [“ clade II”]. |
8 Fertile pinnae nearly in plane of the blade (like a closed Venetian blind); fertile leaves 12-20 cm wide |
8 Fertile pinnae usually twisted out of the plane of the leaf axis, often nearly to 90° (like an open Venetian blind); fertile leaves 8-12 cm wide |
7 Leaves not dimorphic, or only slightly so, deciduous ( D. goldieana), evergreen ( D. ludoviciana) , or else with usually deciduous fertile and semi-evergreen sterile fronds ( D. celsa); fertile leaves lanceolate to ovate in outline, generally 1.5-4× as long as wide; pinnae mostly 3-5× as long as wide; scales at base of petiole dark brown with tan margins. |
9 Costa with bullate (blistered-appearing) scales abundant, usually dark; [naturalized exotic]; [“ clade V”] |
9 Costa lacking bullate scales; [native, sometimes also cultivated]; [“ clade III”]. |
10 Leaves evergreen, fertile only toward the tip, the fertile pinnae and segments narrower than the sterile and more widely spaced; scales at the petiole base light brown, not shiny. |
11 Fertile leaflets only slightly narrower than the sterile leaflets and spaced similarly along the rachis; teeth tapering to sharp points; spores shrunken and irregular |
11 Fertile leaflets much narrower and obviously more widely spaced along the rachis than the sterile leaflets; teeth triangular ( acute); spores full |
10 Leaves deciduous or semi-evergreen, fertile throughout or nearly so, the fertile pinnae and segments not differentiated from sterile ones; scales at petiole base medium to dark brown, shiny or not. |
12 Sterile leaves semi-evergreen; fertile leaves deciduous with sori submedial, not touching the costule at maturity; leaf blade lanceolate, usually 2-4× as long as wide, gradually tapering at the apex; scales at the petiole base medium to dark brown, with a narrow black central band |
12 Leaves deciduous with sori medial, touching the costule at maturity; leaf blade ovate to narrowly ovate, usually 1.5-3× as long as wide; abruptly tapering at the apex; scales at the petiole base dark brown, nearly black, with a narrow pale margin |