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PACIFIC SCIENCE, VoL XIII, April, 1959 
tinue downward into the vascular cylinder. 
In addition, the most lateral pair shown 
on the near side of the stem unite. This 
union of adjacent laterals, mentioned 
above for D. Menziesii, is characteristic of 
some Heliantheae with opposite leaves, 
and has been reported by Carlquist (1957c) 
for Fitchia and Oparanthus. 
5. Multilacunar, verticillate leaves. Example: 
D. railliardioides (Fig. 11). Five traces, re- 
lated to 5 gaps, enter each leaf at a node, 
which usually consists of 3 leaves. As in 
D. laxa and D. laevigata, increase in num- 
ber of veins at the leaf base is accom- 
plished by branching of the laterals. The 
occurrence of a multilacunar condition at 
a verticillate node is of particular signifi- 
cance because, according to Dr. 1. W. 
Bailey (personal communication), this 
condition has never been reported in di- 
cotyledons. The author (1957^) suggested 
that it may occur in Arg^roxiphium Gray- 
anum, a species which was demonstrated 
to have alternate leaves with multilacunar 
nodes, but in which rare individuals have 
verticillate leaves. 
The great diversity of nodal types in Du- 
hautia is of considerable interest. Despite this 
diversity, however, a marked contrast with 
Wilkesia occurs in regard to branching of 
veins in the leaf base. Wilkesia has verticils of 
numerous leaves, each of which is related to a 
trilacunar condition (Carlquist, 19‘yld, fig. 
18). At the leaf base, the laterals are at the 
Figs. 11-14. Reconstructions of nodes of Dubautia (based on serial sections). (11) D. railliardioides, X 6. 
(12) D. Menziesii, X 11.5. (13) D. laevigata, X 5.6. (14) D. laxa, X 6.5. Darker lines represent veins; lighter lines 
represent the outlines of a nodal segment including leaf bases. 
