410 BOTANICAL GAZETTE | DECEMBER 
through the ramular gaps in O. cimnamomea, and occasionally 
through foliar gaps; and neither is there a transition in the 
nature of the connecting tissues, nor any line at which we can 
say, the cortical tissues lie externally to this and the medullary 
tissues internally. 
4. The cortical and the medullary brown sclerenchyma some- 
times fuse through ramular gaps in O. cimnamomea. 
5. Portions of stem of O. cimnamomea have been found which 
are of the ‘‘gamostelic” type of Van Tieghem. The medulla 
in gamosteles is granted to be morphologically a cortical tissue. 
The conclusion is evident for O. cimnamomea at least, and if 
it be granted that the medullary tissues of this species are 
morphologically equivalent to the cortical tissues, then biological 
principles alone would demand a like conclusion for the other 
species. 
Third, of what type is the vascular system of O. cinnamomea? 
Again the facts must form the basis for a decision: 
1. The young stem of O. cinnamomea possesses an entirely 
closed hollow vascular cylinder, sheathed with phloem and 
broken only immediately above the exit of a leaf trace ; and et 
a level higher up the cylinder is entirely closed again. There is 
a medulla and an internal endodermis. 
2. In older plants the leaves are more frequent, and the gaps 
extend through several internodes; but yet the cylinder is the 
unit. The cylinder of phloem is quite rarely broken, except 
- where branching takes place. 
3. There is an internal endodermis which is persistent 
throughout the entire central cylinder of the stem. 
4. As a rule the internal endodermis bends out opposite leaf 
gaps. 
5. There is an internal phloem in portions of some plants. 
6. Not only does the cylinder of external phloem remain 
practically unbroken, but opposite leaf gaps there is on the 
inner side a proliferation of sieve tubes. In O. regalis Janczewski 
found isolated sieve tubes in the parenchyma filling the leaf 
gap; and the same thing is true of O. cinnamomea. 
