4 F E R N S OF NORTH AM E R IC A .
sporangia have a ring of from fifteen to seventeen joints.
The spores are bean-shaped, and have a decidedly roughened
or wrinkled surface.
This fern is very fragrant in drying, so that a few
fronds of it will serve to perfume a whole bundle of dried
plants. It has a larger and broader frond than the European
A . rigidum, but certainly presents no points of specific distinction;
and some of the Oregon specimens collected -by
Mrs. Summers near the Willamette River are so nearly typical
rigidum that they would not be challenged if mixed with
European specimens. In the South of Europe is a paler and
less acutely serrated form of the same species, the A .
diim, of Link.
Plate X L V I.— Aspidium rigidum, var. argutum. The specimen
represented was collected in Santa Cruz County, California, by Dr.
L. C. Yates. Fig . 2 is a fertile pinnule, enlarged. • Fig . 3, a sterile
pinnule from one of the lower pinnæ, enlarged. Fig. 4, a magnified
indusium. Fig. 5, a spore.