Two distinct species, differing mainly in tetrasporangial features, ha
ve been confused under the name Anotrichium tenue. In true A, tenue th
e tetrasporangia are borne terminally on a small number (5-8) of whorl
ed pedicels. In the other, A. secundum, comb, nov., the tetrasporangia
are borne subterminally and adaxially on a relatively large number (8
-50) of whorled pedicels.