26 Wisconsin Academy of Sciences , Arts and Letters. 
III. Branches uniform , all arcuate-divergent; hyaline cells without fibrils , 
those of the branch leaves with one or two central rows of jpores. 
Hyaline cells of branch leaves with 5—10 pores in one row, 
S. niacropliyllum, 27. 
Hyaline cells of branch leaves with 40 — 60 pores in two 
rows. S. Floridanum. 1 
Of the species enumerated the following are reduced by M. Cardot: 
SS. medium, papillosum, Austini and affine are sub-species of S. cyrabi- 
folium; S. laricinum of S. subsecundum; S. squarrosum of S. teres; S. 
Girgensohnii of S. acutifolium. and S. cuspidatum of S. intermedium. 
S. rubellum Wils. becomes a variety of S. acutifolium; S. Muelleri 
Schimp. is a synonym of S. molle; S. Mendocinum S. & L. of S. cuspi¬ 
datum; S. sedoides Brid. of S. Pylsesii. 
S. cyclophyllum is believed to be an immature state of S. subsecundum, 
but is retained in the Key. 
ANDREiEA, p. 25. 
Costa 0. 
Leaves incurved, minute, rotund-obtuse, deeply bi-ventri- 
cose. A. parvifolia.* 
Leaves spreading or secund, acuminate, not ventricose A. petrophila, 1. 
Costate. 
Costa vanishing below apex . • . . . A. rupestris, 2. 
Costa excurrent . A. crassineryium, 3. 
MICROMITRIUM, p. 37. 
Spores 63 n diameter, leaves serrate . . . M. megalosporum, 1. 
Spores 25 n diameter, nearly smooth, leaves serrate above M. Austini, 2. 
Spores a little smaller, papillose, leaves nearly entire . M. synoicum, 3. 
EPHEMERUM, p. 37. 
Leaves not costate.E. serratum, 1. 
Leaves costate. 
Costa ending below or at apex. E. coliserens, 6, 
1 Cardot: 1. c., p. 22. 
a Muller: Flora 1887. 219. 
