Megalastrum biseriale is similar but differs by inequilateral basal pinnae (at least in large leaves), scalier leaf axes abaxially, and pinna rachises abaxially with longer hairs (0.
0 cm long, inequilateral, longer basiscopically; pinna rachises on both surfaces very sparsely glandular, densely pubescent, densely and conspicuously scaly, the hairs 0.
0 cm long, inequilateral, elongated basiscopically; pinna rachises abaxially eglandular, without hairs or (more rarely) pubescent basally, scaly, the hairs (when present) 0.
Pinnules or segments (at least proximal ones) crenate to lobed; basal pinnae usually inequilateral 6.
Laminae basally 3-pinnate-pinnatisect; basal pinnae 25-40 cm long, inequilateral (prolonged basiscopically); pinnules sessile to short-stalked but not adnate; Colombia to Bolivia 23.
5 m long, basally 3-pinnate-pinnatisect, medially 2-pinnate-pinnatisect; lamina rachises without hairs abaxially; basal pinnae 20-30 cm long, inequilateral, longer basiscopically; pinna rachises abaxially eglandular, pubescent, scaly, the hairs 0.
falcatum has basal pinnae equilateral or nearly so, not inequilateral by being greatly prolonged basiscopically.
0 cm long, usually slightly inequilateral, sometimes equilateral; pinna rachises abaxially eglandular, pubescent, sparsely scaly, the hairs ca.
1 m long, strongly inequilateral, pinnules acroscopically reduced toward bases of pinnae; pinna rachises abaxially glandular with sessile to short-stalked glandular hairs, adaxially pubescent and glandular, hairs 0.
5 m long, to 3-pinnate-pinnatisect at base, 2-pinnate-pinnatifid medially; basal pinnae to 45 cm long, stalks to 2 cm long, strongly inequilateral, pinnules acroscopically slightly reduced toward the bases of pinnae; pinna rachises abaxially non-glandular, sparsely pubescent, very sparsely scaly, hairs 0.
0 mm (1-2 times longer than broad), ascending (80-55[degrees]), fully adnate, inequilateral at bases, basiscopically decurrent, most segments lunate to deltate with the tips obtuse to truncate (Fig.
0 times longer than broad), weakly ascending (80-75[degrees]), inequilateral at bases, fully adnate, long-deltate to oblong, the tips obtuse (Figs.