1 68 Hill. — On the Seedling- Structure of certain Piperales. 
and the protoxylem occupying a position corresponding with that taken up 
by the same tissue of the opposite seed-leaf. As soon as these changes 
(the details of which are figured in Diagram III) have been effected, an 
endodermis puts in an appearance, and the central strand has a typical 
root-like appearance. 
The fact that the two cotyledon-bundles fused with the plumular 
a , b, c, d , eg \ plumular bundles ; m, merismatic tissue ; m. i., m. 2., m., 3., merismatic bundles ; 
C. 1., C. 2., cotyledon-traces; ph phloem. The heavy arrows indicate the protoxylem of the 
cotyledon-traces. 
traces at slightly different levels is probably to be accounted for by the 
cotyledons themselves being inserted at slightly different levels. 
There is no definite rotation of the protoxylem elements ; they seem- 
ingly occupy their exarch position owing to the fact that the metaxylem 
moves away from and leaves them isolated, a reunion being afterwards 
effected. 
