26 FOOTNOTES FROM 



earth, in proportion to their size, as the roots of many 

 trees. In some cases they consist of small thread-like 

 fibres, or long creeping underground stems ; while in 

 others they are aerial, like those of orchids, being deve- 

 loped in the form of a thick silky down of a pale brown 

 colour, imbedded among the leaves close to the stem. 

 This last variety of root is to be seen chiefly in species 

 that grow in moist or watery places, where they act as 

 sponges to attract and preserve the humidity of the plants, 

 when the moisture around them is dried up. In con- 

 nexion with their roots we observe a striking provision 

 of nature for the welfare of mosses in unfavourable cir- 

 cumstances. As the most delicate fibres hardly penetrate 

 beyond the surface of the soil, which in dry, sultry 

 weather speedily parts with its moisture, the mosses 

 would perish were they entirely dependent for their 

 nourishment upon their roots. But every part of them, 

 and especially the leaves, is endowed, to a remarkable de- 

 gree, with the power of imbibing the faintest moisture from 

 the air, and reviving, even when apparently withered 

 and dead, on the recurrence of a shower of rain. The 

 roots therefore, in most instances, serve only to attach 

 the plant to its growing-place, the functions of nutrition 

 being performed indiscriminately by its whole surface. 



The leaves of mosses are their most prominent parts. 

 To the careless and superficial eye, accustomed to look 

 at a tuft of moss as merely a patch of velvety green- 

 ness, creeping over an old tree or dyke, the leaves of all 

 mosses may appear precisely similar; but the attentive 

 observer who examines them under a microscope, will 

 find that the leaves of different kinds of trees are not 



