146 
BEAUTIFUL FERNS. 
Hab. — Discovered by Thomas Nuttall in crevices of rocks along the 
Schuylkill River, near Philadelphia ; also found along the Wissahickon 
Creek in the same vicinity. Lancaster County, Pennsylvania, Prof. Thomas 
C. Porter. On moist cliffs of sandstone in the Cumberland Mountains, 
East Tennessee, Prof. F. H. Bradley. Hancock County, Alabama, Hon. 
T. M. Peters. Mine-la-Motte, Southern Missouri, on sandstone rocks. Dr. 
Engelmann. 
Description. — The root-stocks of this little fern are creep- 
ing, branched and often entangled, and chaffy with narrow lance- 
acuminate dark-fuscous scales. The cellular structure of these 
scales is similar to that of the scales of A. ebeneum, the cells 
being oblong-rectangular, and arranged in straight longitudinal 
rows. The stalks are from two to four inches long, and slightly 
chaffy when young : they are brown and shining at the base, but 
green higher up, except that a narrow line of brown is continued 
up the under side of the stalk nearly or quite to the base of the 
frond. A section made near the lower extremity of the stalk is 
nearly semicircular, and discloses two roundish fibro-vascular 
bundles side by side near the middle, and a minute thread of 
sclerenchyma, or hard dark tissue, on the inner side of each 
bundle. A section just below the frond shows the two fibro- 
vascular bundles united into one, and the angles of the stalk 
slightly extended, forming very narrow wing-like borders. The 
minute inner filaments of sclerenchyma are never continued far 
up the stalk, and are sometimes wanting altogether. 
The frond is from three to six inches long, and usually half 
an inch to an inch broad at the base, from which the general out- 
