Flora of North America species comparison

broadly lanceolate to oblong-lanceolate, sometimes amplectant, usually abruptly narrowed from distinct, asymmetric shoulders, 1–2.2 × 0.17–0.5 mm;

margins serrate, commonly spinose at the shoulders, with one shoulder more deeply incised and less regularly spinose or dentate than the other;

apex subulate, sharply pointed, and sometimes recurved;

costa occasionally absent at the base, strong distally, percurrent, excurrent, or ending near the apex, toothed abaxially;

areolation lax in proximal third, more compact distally;

median laminal cells usually in diagonal rows upward from costa to margin, smooth;

distal laminal cells smooth.

linear-lanceolate to ovate-lanceolate, sometimes narrowed from distinct shoulders, 1–2.4 × 0.17–0.3 mm;

margins usually coarsely and irregularly serrate distal to the proximal third, often with spines, but varying to scarcely serrate;

apex tapering gradually to a sharply pointed acumen, absent papillae;

costa usually absent, but sometimes suggested by a few thick-walled cells or an obscure double layer of undifferentiated cells, smooth;

areolation lax proximally and somewhat firm distally;

median laminal cells in vertical rows, smooth;

distal laminal cells smooth.

with columella occasionally persisting to maturity;

stomates scattered throughout.

with columella resorbed before meiosis;

stomates only at the base.

spherical or reniform, 47–95 × 40–62 µm.

spherical or reniform, 55–106 × 27–75 µm.