Flora of North America species comparison

less than 15 cm.

usually 10 or fewer, yellow or brown, 0.5–1.5mm diam. 1 cm from base.

primordia glabrous.;

leaf sheath closed.

to 6 pairs, ascending, usually approximate or overlapping except in shade forms, distance between 1st and 2d pinnae not or slightly more than between 2d and 3d pairs, basal pinna pair commonly much larger and more divided than adjacent pair, lobed to tip, basal pair oblong to oblong-lanceolate with lobed margins, remainder broadly spatulate with entire margins or 1 or more shallow lobes, apex rounded, venation pinnate.

stalk 0–3(–10) mm, to 1/4 length of trophophore rachis;

blade ± gray-green, dull, oblong-linear to deltate, 1–2-pinnate, to 6 × 5 cm, firm.

short-stalked or nearly sessile (long-stalked in forms of B. simplex and B. pedunculosum) arising from the middle or high on common stalk (low in some individuals of B. montanum, B. mormo, and B. simplex), blade usually 1 per plant, appearing in spring and dying in summer or fall, absent during winter, mostly linear to oblong to oblong deltate (deltate in B. lanceolatum), lobed to 1–2(–3)-pinnate, mostly less than 2.5 cm wide when mature, herbaceous to leathery.

1–3 pinnate, 2–3 times length of trophophore.

long- or short-stalked, arising from middle to distal portion of common stalk, well above ground level (low on common stalk, near ground level in some forms of B. simplex), always present, stalks and rachis only slightly flattened, not fleshy, 0.5–2 mm wide.

stalk lacking idioblasts.

lobes and segments, when present, asymmetric, either borne basiscopically or acroscopically.

=45.

=180.