Il6 BOTANICAL GAZETTE [august 



their base with the inner bundles of the stem. The small bundles 

 of the leaf trace come from branches of the peripheral bundles. 

 They, as well as the central bundles, go with or without branching 

 into the petiole, which is merely a continuation of the stem. 



In an elaborate discussion of the vascular anatomy of the 

 Piperaceae, Weiss (19) deals with n species of Peperomia and 

 8 of Piper, and draws the conclusion that in the Piperaceae there 

 is a transition from the monocotyledonous to the dicotyledonous 

 type of bundle. 



By far the most detailed account is that of Dk Bray (3). He 

 used 4 species of Saururaceae, 16 species of Piper, 3 species of 

 Artantlie, and n species of Peperomia. In Piper he found 2-4 

 rings of bundles arranged in two systems, the peripheral and the 

 pith systems. The peripheral bundles are of two sizes; the outer 

 ring is completed by an interfascicular cambium; the leaf trace 

 comes from a peripheral ring, which in the node below is a branch 

 of the central bundles; the vascular supply of the axillary buds is 

 from both peripheral and central bundles. He compares the 

 families of the group, but shows no relationships. 



In Van Tieghem's (17) work on the mucilage canals of Piper 

 he describes in detail the stem of Piper nigrum. He found that 

 there are two circles of bundles; that the pericycle becomes ligni- 

 fied late in the growth of the stem; that the cambium for a long 

 time cuts off segments only on the side toward the pith, and may 

 cut off very late a few segments on the other side ; that the mucilage 

 canals vary in location with different forms and are not continuous 

 through the nodes; and that the canal of the petiole is not con- 

 tinuous with that of the branch. 



The present study of Piper metkysticum was taken up with the 

 idea of giving a modern interpretation to the vascular structure, 

 and to ascertain whether the stem keeps pace with the gametophyte 

 of the group. 



Material 



I am indebted to Dr. W. J. G. Land for the material for this 

 study. It was collected on the Island of Tutuila, Samoa (fig. 1). 

 The plant is a native of the South Sea Islands, and is commonly 



