1887. | BOTANICAL GAZETTE. 239 
the formation of oil-ducts. In Hydrocotyle, therefore, the 
ening the pericarp wall or its ribs. They usually occur be- 
neath each rib, and are normally developed about the simple 
g 
fibro-vascular elements may eventually become > 
The group of strengthening cells may consist of fibrous tis- 
ma, or small- 
celled parenchyma. It may be well marked off from the 
Ssmorhiza, Cryptotenia, Conium an rophyllum (figs 
: 7); or it may gradually merge into the surrounding 
Uissue, as Angelica, Thaspium, etc. In Hydrocotyle. 
Oped in a broad continuous band about the seed-cavity ; 
While in Sanicula, Conioselinum and ®thusa they seem to 
be entirely wanting. In the last named genus they may be 
found in the very tips of the prominent ribs, the position usue 
ally held by strengthening cells being occupied by large and 
