430 



ROSE TRIBE. MANGROVE TRIBE. 



Europe. Of this group (which is ranked by some as a distinct 

 rder) the British genus Sanguisorla, or Burnet, is an example ; 

 the Latin name of which is derived from its supposed power of 

 stanching the flow of blood. Another British genus belonging 

 to it is the Alchemilla, or Lady's Mantle, one species of which is 

 common in fields and gravelly soils. This group is characterised 

 by a greater degree of astringency, than that which usually 

 exists in the true Rosaceae ; although many of the latter also 

 possess this character. The roots of the Potentilla, or Cinque- 

 foil, and of the Tormentil, have been used in tanning ; and the 

 roots of a kind of Bramble afford a popular astringent medicine 

 in North America. The leaves of the Sloe and other species 

 have been used as substitutes for tea ; and the fruit of the com- 

 mon Dog-rose and other allied species has a degree of astringeney, 

 which renders it useful in medicine. 



598. The next order which 

 will be here noticed is that of 

 RHIZOPHOREJE, the Mangrove 

 tribe, which is chiefly remark- 

 able on account of the singular 

 mode of growth observed in 

 the trees belonging to it. The 

 Mangroves are tropical trees, 

 growing on the banks of large 

 rivers, or on the sea-coast, 

 and even within the bounds 

 of the ocean as far as low- 

 water mark. Their mode of 

 rooting consists, not like that 

 of ordinary trees, of divisions 

 of the stem beneath the 

 ground, but (as it were) of 

 arches of roots above it, so 

 that a more extended base is 



formed, and a firmer hold FJ(J 156> _ MANGROVJ5 TREB . 



established, in the loose and 



swampy soil. From the summit of these overbending roots, 

 the trunk of the Mangrove springs, as shown in the ad- 



