THE HAY-SCENTED BUCKLER FERN 319 
plants of Dilatata are often mistaken for Recurva by those 
who are not acquainted with the peculiar points of difference. 
In both Ferns the fronds are broadly lance-shaped, or 
triangular in form, broadest at the base and tapering to a 
point at the apex. The pinnae are set on the rachis either in 
pairs or alternately on opposite sides of it. The fronds in 
both, too, are tri-pinnate at their bases, and bi- pinnate in their 
upper portion. The lowest pinnae in both are arranged upon 
the same plan, being broader than the others, and having the 
lower pinnules on their mid-stems longer and more divided 
than the upper ones, the difference becoming less and less and 
disappearing at the apices of the pinnae. In the same way, in 
both, this difference between upper and lower pinnules is less 
marked on the second pair of pinnules and becomes less and 
less upwards until upper and lower pinnules on the highest 
pinnae are equal in length, the pinnae becoming shorter and 
narrower and less divided until they are finally merged in the 
apex of the frond. In both Ferns, in fact, the form of pinnae, 
pinnules, lobes, and serratures, is of a similar character, as 
also is the venation and the arrangement of the sori, which 
are ranged in lines on each side of the mid-veins of the lobes. 
But in Recurva, the clusters of spore cases are covered by 
kidney-shaped indusia which are fringed on their outer or 
unattached margin. Now let us see what are the points of 
difference between the two Ferns. In the first place, Recurva 
is much smaller than Dilatata, its length ranging from a 
foot to a maximum of about two feet, the leafy portion of 
the frond being about equal in length to the stipes, though 
sometimes shorter. There is, further, the beautiful hay scent 
about its fronds, and most striking feature of all, the lobes of 
the pinnules, instead of being bent and curled under, as are 
the lobes of Dilatata, are slightly bent the other way, so that 
their upper side is somewhat concave, instead of convex. 
This gives a peculiar and very elegant crumpled appearance 
