319 
of these two figworts. These differences are so distinctly 
marked, even to the unaided eye, that identification may safely 
rest on a mere glance at a fragment of the fresh root. In Mary- 
/andica the central cylinder is slender, occupying only about one- 
third of the diameter of the root; it is hence of about the thickness 
of the surrounding cortex, from which it is sharply distinguished 
by its greater whiteness, especially at its tough and lignified outer 
walls. Upon attempting to break the root the cortex is easily 
ruptured and peels off smoothly from the central cylinder which 
bends readily but refuses to break. In /eforella the central cylin- 
der is of ‘softer texture and much larger, occupying the greater 
part of the interior of the root ; its walls are not lignified, nor is it 
sharply marked off in color from the surrounding thin layer of cor- 
tex, which is not readily disengaged from it. The root is easily 
snapped in two, showing an even plane of fracture. 
A comparison of the flowers of these plants shows a curious 
reversal of color characters between them. In Marylandica the 
surface of the corolla tube is green and dull, the interior shining 
and brownish-purple; in /epore//a the outside of the tube is pur- 
plish and shining, the interior green and dull. The color of the 
sterile stamen, deep purple in J/arylandica, yellowish-green in /ep- 
orella is absolutely constant, that is to say, a reference to hundreds _ 
of flowers of each species has discovered no exception. Even i in 
flowers of Marylandica which are pale green nearly throughout, 
the sterile stamen remains purple; conversely, in the most highly 
colored flowers of leporella the green stamen is without the slight- 
est purple tinge. 
The early annual shoots of these plants show some interesting : 
comparative differences. Before the end of April the stouter 
shoots of /eporella are already a foot or more high, four or five times 
as tall as those of Marylandica. In the former the base of the. 
shoot is leafless, often for several inches, and invested with broad, 
appressed, overlapping scales or bracts (modified petioles) ; these 
show a gradual transition into the small lower leaves. The early 
leaves have broad, flat petioles, sometimes nearly half an inch wide ; 
the bases of the blades are mostly entire and sharply truncate. In 
Marylandica the lowest pair of leaves are large and fuily devel- 
Opec, on long slender petioles which rise from nearly the extreme 
base of the shoot. 
