THE WOODSIAS. 97 
Woodsias, the indusium is fixed to the frond underneath 
the sorus. In the beginning, it surrounds the sporangia, 
but early splits into several segments which spread out 
in star shape when the sorus considerably resembles a 
small green flower, the indusium answering to the corolla 
and the sporangia to the essential organs. 
The range of the obtuse Woodsia is almost wholly in 
the United States. One station in Nova Scotia is all 
that is known beyond our limits in the East. Southward 
it extends to Georgia, the Indian Territory and Arizona. 
It isalso reported from British Columbia and Alaska. It 
may occur on any shaded ledge but it is not always to 
be found in what appear to be suitable situations. It 
is usually less common than its counterpart, Cystopteris 
Sragilis. In the southern part of its range, the fronds 
are evergreen but their texture would indicate that this 
condition does not prevail northward. A small and 
more glandular form has been described as the variety 
glandulosa. The common form in fruit is illustrated in 
the Key to the Genera. 
In the West the obtuse Woodsia is represented by 
two other species which are occasionally found as far 
east as northern Michigan. The first of these, Woodsia 
Oregana, is chiefly distinguished by its narrower blade 
covered beneath with flattened hairs and stalked glands, 
its oblong-ovate, toothed pinnze and the much narrower 
segments of the indusium. The second species, Woodsia 
scopulina, has shorter, nearly smooth fronds, with tri- 
angular-ovate pinnae the lowest of which are noticeably 
shortened. The indusium, which consists merely of a 
few hair-like divisions, is difficult to see in ordinary speci- 
mens. In appearance and habitat, both species are 
much like the obtuse Woodsia and at various times have 
been described as varieties of it. 
