192 
Hill and de Fraine . — On the 
Fig. 6), so that in the upper region of the hypocotyl (Diagram 6, Fig. 7) 
there occur two groups of protoxylem ( c . 1 and c. 2), four large bundles 
derived from the cotyledons ( b . 1 and b. 2 , and b. 3 and b. 4), and six 
plumular strands which soon fuse to form two (d. 1 and d. 2, Diagram 6, 
Fig. 8). Tracing these bundles downwards, their behaviour is seen to be 
Diagram 6. Allionia albida. 
very complicated ; the protoxylems c. 1 and c. 2 retain their position, but 
the bundles b. 1, d. 1, and b. 3 anastomose very freely, and so also do the 
corresponding strands on the other side. Concurrently the bundles b. 1 
and b. 3, and b. 2 and b. 4, show certain rotatory movements which tend to 
bring their protoxylems into the intercotyledonary plane and into the 
exarch position, but for some space downwards these movements lead to 
nothing definite owing to the presence of the strands d. x and d. 2, which 
