78 
others, water-ferns, are grown in the aquatic house, No. 9. Prob- 
ably the largest number of species are to be found in house No. 
10, where the plants are arranged along the benches in taxo- 
nomic sequence. But the plants in No. 11 are of rather more 
general interest. In this house are to be found ferns of the 
greatest variety of habit and appearance, from simple-leaved 
unfern-like species of Aspleninm, Doryopteris and others, to tree- 
ferns with tall trunks and leaves many times divided ; from the 
bizarre, well-named “‘ staghorn” ferns to the Lygodiums, ferns 
whose leaves may climb to a height of ten feet or more. Not 
the least interesting are the plants of the Marattia alliance, a group 
of ferns whose ancestors can be traced back in geological history 
to the coal-measures, strata whose age is variously estimated up 
to fifty millions of years 
Fossil specimens of these ancestral forms and of other types of 
ancient fern-plants are to be found in the palaeobotanical collec- 
tions in the basement of the museum building. aad of fossil- 
ferns is becoming increasingly important nowadays, as it is gen- 
erally accepted that somewhere in this alliance ae exist the 
ancestral forms of all our modern vascular plants with the excep- 
iv of the ea and horsetails. These last mentioned groups, 
ugh commonly designated as ‘‘fern allies,” are really less 
ae related to ferns than are the cycads, the conifers and 
probably also the dominant modern group, the flowering plants. 
In coal-measure times, plants of the lycopod alliance formed the 
dominant type of vegetation, including great tree-like species of 
“horsetails” and ‘‘lycopods,”’ 100 feet high and more, some of 
which had developed the seed-bearing habit. Impressions of the 
trunks and leaves of some of these plants are also to be seen in 
the collection of fossil plants. 
he remaining fern collections of the Garden are comprised in 
the systematic collections on the second and third floors of the 
building. On the second floor, ferns occupy their proportionate 
share of the series of public exhibits, and are found in the micro- 
scope exhibit, in which a few of the characteristic features of fern 
anatomy are shown, in the general display herbarium, and in the 
local flora stands, the last-named containing forty-three species. 
