Publication: Fern Bulletin 6: 30.
selected vouchers: WTU
Notes: BEN 304: "Several field characters distinguish plants of I. minima from plant of I. nuttallii. First, I. minima has an incomplete velum covering up to 75% of the sporangium whereas, I. nuttallii has a complete velum covering 100% of the sporangium. Second, I. minima has spinulose textured megaspores ranging 290-350 mm in diameter. In contrast, I. nuttallii has smooth to tuberculate textured megaspores ranging 360-600 mm in diameter. Third, I. minima is generally a smaller plant with leaves up to only 4 cm long whereas, I. nuttallii is usually larger plant with leaves up to 20 cm long."