THE EVOLUTION OF PLANTS 599 
connection. So closely does it resemble a certain fern 
(Lomaria) that the botanist Kunze, who first described it 
when it was brought from Natal to the botanic garden at 
Chelsea, England, supposed it was a fern, and named it 
Lomaria eriopus. The specimen possessed no fruit, which 
would have helped to identify it. Its leaves, with 
circinate vernation, have a pinnately compound blade, 
and leaflets with pinnate dichotomous venation. Two 
or three years later another botanist, examining it more 
closely, pronounced it a "fern-like Zamia or a Zamia-like 
fern." These facts show how puzzling the specimen was, 
and how closely a plant may resemble both a cycadophyte 
and a fern. In a sense this plant may be called a living 
fossil. Specimens have since come into flower in botanic 
gardens, and the typical cycadaceous cones (Fig. 420) 
leave no doubt that the plant is a true cycadophyte. 
518. Derivation of New Types. Attention should here 
again be called to the fact that the theory of evolution does 
not teach that one given species becomes transformed into 
another, but simply that new species are descended from 
older forms which may or may not continue to exist. It 
is not supposed, for example, that ferns developed into 
cycads, and cycads into higher gymnosperms, but that there 
has been an unbroken line of descent (possibly more than 
one) in the plant kingdom ; that closely related forms (like 
ferns and cycads) have descended from a common ancestral 
type which may or may not now be found. We must not, 
in other words, expect necessarily to find in fossil forms the 
direct ancestors of those now living, although a study of 
their structure is of the greatest value in enabling us to 
understand the genetic relationships of the great groups 
of plants. 
