On some points in the Anatomy of Ipomoea 
versicolor, Meissn. 
BY 
D. H. SCOTT, M.A., Ph.D., F.L.S. 
Assistant Professor in Biology (. Botany ), Royal College of Science, London. 
With Plates XII and XIII. 
I POMOEA versicolor , Meissn., a native of Mexico, is fre- 
quently grown in greenhouses under its older name of 
Mina lobata , Cerv., and has also been described as Qua - 
moclit Mina , George Don. Like so many of its genus and 
order it is a twining plant, and, though an annual, attains 
a considerable height during its single season of growth. 
In one of the specimens examined, which was grown in 
a cool greenhouse, the length of the main stem exceeded 
17 ft. (above 5 m.), but no doubt larger dimensions are often 
reached. 
For about the first three internodes above the cotyledons 
the stem is straight. Twining begins in full vigour in or 
about the fourth internode. (See Fig. 1.) 
The younger part of the stem is cylindrical and contains 
a normal ring of bicollateral leaf-trace bundles, the xylem- 
groups of which soon become united by the cambium to form 
a continuous zone of wood. The bicollateral structure, which 
is nearly constant throughout the order, is very characteristic 
[Annals of Botany, Vol. V. No. XVIII. April, 1891.] 
N 
