33. 
THE MARSH BUCKLER FERN. 
Lastrea thelypteris. 
Plate 11, Fig. 3, Page 331. 
The most delicately herbaceous and fragile of the British 
Buckler Ferns, Lastrea thelypteris is also the only one 
amongst our native species which loves to grow absolutely 
in water. Its common name sufficiently represents this 
peculiar character and habit of the plant. Its botanical 
specific name of thelypteris is a compound word signifying 
Lady Fern, and the species is sometimes called the Female 
Buckler Fern, probably on account of its extreme delicacy 
of form and texture. Some botanists have ranked this 
species amongst the Polypodies, and its truly creeping 
rhizoma certainly gives some reason for its inclusion amongst 
the ‘ many-footed ’ Ferns. In this character of its rootstock, 
indeed, it is essentially different from all the other English 
Lastreas. But the indusium. though small, thin, and of no 
particular shape, is nevertheless present, and thus provides 
a different arrangement from that of the Polypodies. The 
Marsh Buckler Fern is an inhabitant of marshes and 
wet bogs, its rhizomas and rootlets being often entirely 
immersed in water. Over the thick black ooze of a bog 
these rhizomas travel, spreading into quite a network of 
clustered crowns, and sending up here and there waving 
tufts of their delicate fronds, which often offer a beautiful 
contrast to the black bog-water. 
