268 THE WALKING FERN AND HART’S-TONGUE. 
A form called zxtermedia has been described from Iowa. 
In this the fronds are without ears at base and taper to 
the stipes, in which characteristic they resemble the Old 
World species, C. Szbericus. This latter inhabits northern 
Asia and Japan and is the only other species in the genus. 
The word Camptosorus is derived from two Greek words 
meaning bent and fruit-dot and refers to the lines of 
crooked sori. 
The Har? s-Tongue. 
There can be no difference of opinion as to which is 
the rarest fern in Northeastern America. This distinc 
tion is well known to belong to the hart’s-tongue (Scolopen- 
adrium vulgare). So far as known, two limited regions in 
the United States and two in Canada are the only ones in 
the Western Hemisphere in which it grows. On the 
other side of the world, however, it is abundant and 
Shirley Hibberd includes it among the four commonest 
species about London. 
It was first discovered in America near Syracuse, N. Y.., 
by Frederick Pursh who writes that he found it ‘In shady 
woods in the western part of New York, on the planta- 
tion of J. Geddes, Esq.” It was afterward found in 
greater abundance at Chittenango Falls and this place 
is frequently named as the original station, but the re- 
cent rediscovery of Pursh’s station for it has set the 
question at rest. At Chittenango Falls, the plants are 
plentiful, growing on the talus at the base of a limestone 
cliff, where the atmosphere is constantly moist from the 
spray of a nearby waterfall. 
The fronds spread outward ina circular tuft and are 
about half erect. They are dark, glossy green above, 
somewhat lighter beneath, and very thick and leathery. 
