310 PHARMACEUTICAL BOTANY 
layers of thicker-walled cells with brownish walls. Through the 
angles or rib portions of the mesocarp extend the /ibro-vascular 
bundles. Each of these consists of a few spiral, annular and 
simple pored .tracheids and tracheae and many sclerenchyma 
fibers. Between each fibro-vascular bundle and the tip of each 
rib will be found a zone of collenchyma cells. In the mesocarp 
between each two ribs on the dorsal side occurs a single ViTTA or 
oil tube which is lined with a layer of brownish polygonal cells. 
These vittze contain the official oil of fennel. Two vitte gen- 
erally occur in the mesocarp of the commissural side although 
four are reported to have been found in this region of some 
varieties of fennel. 
3. Endocarp, a narrow layer of oe transversely elongated, 
except over the regions of bundles where they may be seen elon- 
gated in several directions. 
4. Spermoderm or Seed Coat, consisting of a layer of somewhat 
‘broadened epidermal cells attached to the endocarp and several 
layers of collapsed cells which are only well defined in the region 
of the raphe. 
5. Endosperm, a central, somewhat reniform mass of more or 
less polygonal cells containing aleurone grains and fixed oil 
globules. Each aleurone grain generally contains a rosette 
aggregate of calcium oxalate and one or two globoids. 
6. Embryo, embedded in the endosperm of the upper region of 
the seed, with its hypocotyl directed upward. 
