ON GENERA AND SPECIES. 25 
Seci. 1. Symplophlebiew. Veins anastomising in various 
ways. 
Hz, Aspidium, Sw., Pleocnemia, Pr., Nephrodium, Schott. 
Sect. 2. Orthophlebiesm. Veins free. 
Ez. Lastrea, Bory., Polystichum, Roth., Didymochlena, Desv. 
Tribe VI. —DICKSONIES, J. Sm. 
Sori marginal, round or linear, furnished with a special 
and accessory indusium, which united form a cyst or groove 
including the sporangia, and opening exteriorly. 
` Bet, 1. Lindsææ, J. Sm. Sori linear, rarely round. 
. e. Lindsæa, Dry., Dictyoxiphium, Hook, Odontoloma, 
J. Sm. 
Sect. 2, Davalliew, J. Sm. Sori round or vertically oblong. 
Indusium cystiform, cuculate or tubular. 
| Ev. Microlepia, Pr., Davallia, Sm., Loxoma, R. Br. 
.. Sect. 3. Trichomanes, J. Sm. Sporangia seated in a free 
columnar receptacle included in or inserted along. the 
|| Vyst. 
Ex. Trichomanes, Linn., Hymenostachys, Bory., Hymeno- 
phyllum, Sm. 
Sect 4. Dicksonim. Sporangia included within a concave, 
bilabiate, or calyciform, reflexed cyst. 
: Pa. Sitolobium, Desv., Dicksonia, L’ Herit., Cibotium, Kaulf. 
| Tribe Ni oC uam, J. Sm. 
.. Sori round intramarginal, receptacle elevated. Indusium 
caly ciform, or lateral, trichiform or absent. 
: Ka Cyathea, Sm., Hemitelia, R. Br., Trichopteris, P resl. 
_ Divisios II. —GLEICHENIACEUE, R. Br. 
m , Sporangia furnished with a transverse ring. Sori round 
E Ls R. Br. Gleichenia, Sw., Mertensia, Willd, 
