183 
The specimen figured is a species of the extensive 
genus Hypnum; but, as the discriminating characters 
dépend upon a microscopie examination of its leaves 
I cannot speak with absolute certainty, though I be- 
lieve it to be the common Hypnum Cupressiforme. 
There is no tribe of plants more deserving the at¬ 
tention of the naturalist than the Mosses; and with 
a little practice in the use of the microscope, and 
the Muscologia Britannica as a guide, the lover 
of nature will soon acquire the power of distinguish- 
ing any of our native species which may fall in his 
way. The small vessels (thecæJ elevated upon 
slender stalks (setœ) contain fine grains termed spores 
(sporœ ), which are the reproductive organs of the 
plants, analogous to seeds in flowering species. The 
theca is furnished with a lid (operculum), which falls 
