Notes on the Ferns of Kentucky, III. Cheilanthes feei on Silurian Limestone in Kentucky

One of the most unusual habitats in which to find ferns is the formation of limestone of Silurian Age upon which cedar barrens develop in Kentucky. Recently the author had occasion to study and collect the plants and ferns found on two of these outcroppings-one in Bullitt County, near Cedar Grove-the other, in Nelson County, near Bardstown, along Cedar Creek. The flora on these barrens is distinctive and alike on both. The actual barren is made up of a grayish clay which is very slippery when wet, yet hard and brittle when dry, cracking to a depth of about a centimeter. This area is open and barren, having only occasional patches of Rhamnus lanceolata and Rhus aromatica, with an infrequent Celtis bush and cedar tree. Peeking out from under this shrubbery are delicate Shooting Stars (Dodecatheon meadia), pale blue Sisyrinchium angustifolium, white Nothoscordum bivalve, little Scutellaria parvula, and bright yellow-orange Lithospermum canescens. So it is in May. Later in the season, in August, the flora is quite different, the predominating species being Agave virginica, Sabatia angularis and its white form, several Rudbeckias, Echinacea pallida, Ratibida pinnata, Petalostemon candidum, Thalictrum revolutum, Asclepias verticillata, A. tuberosa and Acerates viridiflora. Just back of this barren is a sort of transition zone of mesophytic woods containing chestnut-oaks, hackberry, and sassafras, canopying a humus-containing soil in which Frasera caroliniana grows, along with Botrychium virginianum and Asplenium platyneuron. Back in this wooded area is an outcropping of Silurian limestone, 53