1916} HOFFSTADT—PIPER METHYSTICUM 121 
a short time xylem entirely surrounding phloem, and vice versa. 
Bundles may join with either the phloem or xylem together. 
They may lie side by side and union may occur either in the xylem 
or in the phloem. Not infrequently the xylem of two bundles 
may unite, and the phloem of a third join the phloem of either of 
the others. Strands become separated from bundles and several 
of these may coalesce to make a bundle, or they may join with 
other bundles. One often gets cross-sections and longitudinal 
sections of the same bundle in the same section. 
The bundles in one internode are in the periphery, and through 
the following two internodes are pith bundles. The position in 
the pith often gives the appearance of two complete rings and one- 
half of a third ring, when the number of bundles is large; but care- 
ful study shows that there are really only two rings. The number 
of bundles reaches 45-50 in the pith. 
Description of stem in detail 
As previously stated, the stem of Piper methysticum has two 
sets of bundles which may be designated as the peripheral ring and 
pith or medullary rings, two in number, and an irregular half- 
ring which gives the appearance of a third ring at times. The 
bundle type is open collateral endarch, oriented for the most 
part in the usual manner. Sometimes, however, one finds the 
protoxylem points appearing in reverse orientation (fig. 10, e-g). 
Union is often incomplete and one finds double bundles persisting 
in the internode, and these may be of two types. The xylem points 
or the phloem points may be together (figs. 11, 12). 
The peripheral ring of bundles is formed of two sizes: the 
primary, those differentiated first; and the secondary, termed 
supplementary by Dr Bray (3) (fig. 13). The secondary bundles 
are branches of the primary bundles and lie between them. 
More than one primary bundle may contribute to a secondary one 
(fig. 9); that is, two bundles may branch and the branches join. 
The number of secondary bundles varies from none to 3, according 
to the age and size of the stem. Near the tip there are none 
(fig. 4), as observed by Scumrrz (12). 
