Jones: Flora of Illinois 31 



7. Larger ferns with the leaves membranous to coriaceous, consisting of several 

 layers of cells; sporangia not as above. 

 8. Sporangia large, sessile, opening by a transverse slit, borne in a stalked 

 terminal spike or loose panicle, the sterile blade appearing lateral; verna- 

 tion erect or inclined 6. Ophioglossaceae 



8. Sporangia small, stalked, borne in clusters (sori) on the back of ordinary or 

 modified foliar leaves, or in pod-like divisions of modified leaves; verna- 

 tion usually coiled. 

 9. Sporangia covering some or all divisions of the fertile leaves, densely 

 crowded, short-stalked, globose, opening by a longitudinal slit into two 



valves; annulus none; veins free 7. OsMUNDACEAE 



9. Sporangia in sori on the back or margin of ordinary or modified leaves, 

 long-stalked, opening by a nearly complete vertical ring (annulus).... 



8. POLYPODIACEAE 



2. Leaves quadrifoliolate, clover-like, long-petioled ; sporocarps ovoid, borne at the 

 base of the petioles and containing both megaspores and microspores; plants 



perennial with slender rhizomes 9. Marsileaceae 



.Plants not attached by roots, minute (5-25 mm. broad), free-floating; leaves imbri- 

 cated, 2-lobed; sporocarps in pairs beneath the stem 10. Salviniaceae 



Section 19. Gymnosperms (except Hudsonia) 



, Leaves glabrous. 



2. Leaves (and cone-scales) spirally arranged, i.e., fascicled or alternate, never op- 

 posite or whorled. 

 3. Fruit berry-like, red, 1 -seeded, the seed nearly enclosed by the pulpy aril; micro- 



sporophylls with 3-8 pollen-sacs; cotyledons 2; leaves linear, evergreen 



1 1 . Taxaceae 



3. Fruit a woody cone, or 1-3-seeded, bluish, berry-like. 



4. Seeds winged; microsporophylls with 2 pollen-sacs; cone-scales and bracts 



mostly distinct; branchlets not deciduous 12. PiNACEAE 



4. Seeds wingless; microsporophylls with 3-8 pollen sacs; cone-scales without dis- 

 tinct bracts ; lateral branchlets (in our species) deciduous, the leaves light 



green, flattened, 2-ranked; bark fibrous 13. Taxodiaceae 



2. Leaves and cone-scales opposite or whorled, the leaves small, scale-like or subulate 



14. Cupressaceae 



.Leaves pubescent, subulate, numerous, 1-2 mm. long; low shrubs 10-20 cm. tall; 



flowers yellow; capsule ovoid, 3-angled, glabrous, l-2-seeded 



Hudsonia in 107. CiSTACEAE 



