202 The Ohio Naturalist. [Vol. XIV, No. 1, 



POLYPODIACE^. 



I. Sori naked or with marginal indusia. 



1. Sori naked or at least without a typical indusium and not covered 



by the reflexed margin of the leaf-blade. 



POLYPODiAT^. Acrostichum, Polypodium, Phegopteris, Vittaria. 



2. vSori marginal and usually covered by the reflexed margin of the 



leaf-blade. 



PTERiDAT.E. Notholaena, Adiantum, Petris, Pteridium, Pellaea, 



Cryptogramma, Cheilanthes. 



II. Sori with special indusia. 



1. Sori linear or oblong, more then twice as long as broad. 



ASPLE\i.\T^. Anchistea, Lorinseria, Asplenium, Athyrium, 

 Phyllites, Comptosorus. 



2. Sori roundish, not more than twice as long as broad, usually nearlj'' 



circular in outline, dryopteridat.e. Dryopteris, Polystichum, 

 Oleandra, Nephrolepis, Davallia, Dennstaedtia, Filix, Woodsia, 

 Matteuccia, Onoclea. 



Synopses of Marsileace^ and S.vlviniace^. 



MARSILE4CE^. 



a. Leaves with 4 leaflets; sporocarp bean-shaped, with 

 several to many cavities. Marsilea. 



b. Leaves grass-like; sporocarp globose, with 2-4 cavities. 



Pilularia. 



SALVINIACE^. 



a. With true water roots; sporocarps (sori) on the floating 

 leaves. Azolla. 



b. Without roots but with root-like dissected leaves; 

 sporocarps (sori) at the base of the submerged dis- 

 sected leaves. Salvinia. 



Synopsis of the Calamophyta. 



I. Sporophyte homosporous; leaves united into a sheath with teeth; 

 sporophylls shield-shaped, with sack-like sporangia on the lower or 

 inner side; stem with a ring of vascular bundles and central pith which 

 is usually hollow. Equisete.«, EQUISETALES, equisetace.e, 

 Equisetum. Horsetail, Scouring-rush. Note. — The lowest forms are 

 the large species with evergreen aerial stems of one type; the most 

 specialized species have two types of annual aerial stems. 

 II. vSporophyte heterosporous; leaves in whorls, free or united into a sheath; 

 all fossil; some of the groups placed here are still imperfectly known 

 and may be homosporous. 



1. Stems with a central triarch vascular bundle; leaves not fused into 



a sheath; sporangia stalked, on the upper side of the sporophyll. 

 Paleozoic herbs or trees. 



Sphenophylle/E, SPHENOPHYLLALES. 



a. Leaves small or medium in size, usually inure or less 

 wedge-shaped. Sphenophyll.^ce.e, Sphenophyllum. 



b. Leaves large, deeply pinnatifid. 



psEUDORORNi.\CE>E. Pseudobornia. 



2. Stem with a ring of vascular bundles, increasing in diameter liy a 



cambium zone, and with a central pith, usually hollow; leaves 

 whorled, free or at first united; Paleozoic plants often tree-like 

 Calamarie.e, CALAMARIALES, calamari.vce.e, Calamodendron, 

 Calamites, and other genera are recognized. 



