48 American Midland Naturalist Monograph No. 7 



16. Cheilanthes Sw. — Lip Fern 



1. Leaves 3-10 cm long, 1-2 cm wide, densely tomentose beneath; 

 stipes becoming nearly or quite glabrous; indusia continuous; 

 among rocks, principally limestone, not common; chiefly in the 

 western and southern counties C. feei Moore 



1. Leaves 10-30 cm long, 2-6 cm wide, hirsute- villosulous beneath; 

 stipes persistently hirsute; indusia discontinuous; chiefly on non- 

 calcareous rocks in the southern counties 



C. lanosa (Michx.) D.C.Eaton 



17. Pteridium Gled. ex Scop. — Bracken 



P. latiusculum (Desv.) Hieron. Open woods, common. [Pteris 

 aquilina and Pteridium aquilinum of auth., non L.]. 



9. Marsileaceae R.Br. 



1. Marsilea L. 



M. quadrifolia L. European Marsilea. Ponds, etc., introd. from 

 eastern U.S.; native of Europe. Known from Jackson, McDonough, 

 and Vermilion counties. 



10. Salviniaceae Reichenb. 

 1. Azolla Lam. 

 A. mexicana Presl. Mosquito Fern. Floating on stifl water, not 

 uncommon; of local distribution, but chiefly in the western counties. 



Division IL Spermatophyta. Seed Plants 

 Subdivision L Gymnospemiae. Gymnosperms 



1. Taxaceae Lindl. — Yew Family 



1 . Taxus L. — Yew 



T. canadensis Marsh. Canada Yew. Ground-hemlock. Wooded 

 hillsides near streams, rare; n.w. 111., extending southeastward to La 

 Salle and Kankakee counties. 



2. Pinaceae Lindl. — Pine Family 



L Leaves evergreen, in fascicles of 2-5, surrounded at the base by a sheath; 



cones usually maturing the second year 1. Pinus 



1. Leaves deciduous, in clusters of 20-40 on short lateral spurs; cones 



maturing the first year 2. Larix 



1. Pinus L. — Pine 



1. Leaves five in each fascicle, slender, bluish-green, 6-12 cm long; 

 each leaf with one vascular bundle; cones cylindrical, often 

 curved, pendent, 10-15 cm long; n. 111., known from Carroll, 

 Cook, Jo Daviess, Lake, La Salle, Lee, Ogle and Winnebago 

 counties. Eastern White Pine P. strobus L. 



1 . Leaves two or three in a fascicle ; each leaf with two vascular 

 bundles. 



