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 Rhizome short, erect; all the pinnae interconnected by orbicular auricles or triangular wings between the pinnae; leaf blade lanceolate, > 4× as long as wide, tapering to both ends from near the middle (the largest pinnae near the middle of the blade); primary pinnae alternate
1 Rhizome long creeping; all the pinnae interconnected by a narrow rachis wing, or the proximal 1-3 pairs of pinnae free; leaf blade broadly triangular, broadest at or near the base (the largest pinnae the basal or next pair); primary pinnae opposite.
..2 Rachis wings present between the two basal pinna pairs; basalmost pinnae (2-) ca. 3× as long as wide; frond blade usually wider than long; rachis bearing on its lower surface relatively few, white to pale tan, narrowly lanceolate scales (these mostly 3-5 cells wide at the base) and hairs 0.1-0.25 mm long
..2 Rachis wings absent between the two basal pinna pairs; frond blade longer than wide; basalmost pinnae 4-5× as long as wide; rachis bearing on its lower surface numerous tan to brown, lanceolate scales (these mostly 6-12 cells wide at the base) and acicular hairs 0.3-1.0 mm long.
....3 Clones/colonies fairly compact, often dense with overlapping fronds; fronds shorter; lowermost pinnae relatively wide (ca. 4× as long as wide), often strongly deflexed and projecting forward from the plane of the upper frond; the overall shape ovate with a long-acuminate tip; spores smaller, average < 60μm; [n = 3n = 90]
....3 Clones/colonies often loose, fronds touching but not overlapping; fronds taller; lowermost pinnae relatively narrow (4.5× or 5× as long as wide), somewhat but not strongly deflexed and not projecting as far forward; overall blade shape deltate (triangular, but again with a long tip) and less rounded at bottom; spores larger, average > 60μm; [n = 4n = 120]