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.

setaceous to linear-lanceolate, 1.1–0.23 × 0.12–0.2 mm;

margins serrate to strongly spinose;

spines 40–60 µm, spreading or recurved to 45°;

or more, sometimes 2-celled;

apex narrowly acuminate;

costa occasionally absent in the proximal third, but usually strong, nearly 1/3 of the base, percurrent or excurrent, spinulose or spinose;

areolation firm proximally and denser distally;

median laminal cells in vertical rows, papillose or occasionally smooth;

distal laminal cells spinose.

with columella occasionally persisting to maturity;

stomates scattered throughout.

with columella resorbed before meiosis;

stomates few, mostly in the proximal half.

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

spherical or reniform, 58–118 × 42–80 µm.