Vegetative Anatomy — Carlquist 
201 
other than venation may suggest the latter 
interpretation. Probably the type of venation 
shown by D, lineam is basic for the genus be- 
cause it is found in conjunction with other 
unspecialized characters in some of the puta- 
tively primitive species. The type of venation 
illustrated by D. mkrocephala seems clearly a 
specialized condition. 
Comparison of leaf venation in Dubautia 
with that of Ar^roxiphium and Wilkesia is 
pertinent in this regard. Paradermal sections 
of Ar^roxtphium leaves reveal that the basic 
venation is similar to that of D, lineam if the 
additional vein series denoted by the writer as 
"upper” and "lower” sets of veins (Carlquist, 
1957^/) are disregarded. Wilkesia (Fig. 10), on 
the contrary, is markedly different from 
Af^roxiphium in its venation. This remarkably 
monocotyledonous venation pattern is char- 
acterized by longitudinal orientation of vir- 
tually all of the major and minor veins. 
Cross-connections between the longitudinally 
oriented veins are infrequent. Although this 
pattern appears to be anomalous in compari- 
son with the types described above, it may 
well have been derived from a type like that 
of Dubautia mkrocephala by means of a more 
nearly exclusive production of longitudinally 
oriented veins. Venation similar to that of 
Wilkesia has been described for another mem- 
ber of Compositae in Schlectendalia luzulae- 
folia, a member of the tribe Mutisieae (Urban 
and Mobius, 1884). 
Nodal Anatomy 
The genus Dubautia is curious because of 
the variation in phyllotaxy and the presence 
of both petiolate and sessile clasping leaves 
within the genus. Both of these characters of 
leaf attachment are related to the vascular 
pattern of nodes. Although the author’s ma- 
terial did not prove sufficient for placing each 
species in a category, the data below probably 
indicate the full range of types which occur in 
the genus. The types indicated include all 
that have been reported previously for the 
family, except for multilacunar nodes with an 
alternate-leaved condition. This latter type 
does not occur in any of the alternate-leaved 
species, which are uniformly trilacunar. As 
some of the examples below show, transitions 
between the recognized types may occur in a 
single stem. 
1. Trilacunar, alternate leaves. Examples: D, 
Sherffiana^ D. lonchophylla. 
2. Trilacunar, opposite (decussate) leaves. 
Examples: D. Menziesii (Fig. 12), D. mon- 
tana^ D. latifolia, D. platyphylla, D, scabra. 
The drawing of D. Menziesii shows, below, 
a trilacunar node with only the traces of 
the facing leaf indicated. Above is a node 
in which both leaves of the pair are sup- 
plied by 4 traces. This node, then, is transi- 
tional between trilacunar and multilacu- 
nar. The additional pair of traces, on the 
far side of the stem, fuse to a single trace 
a short distance below the node. Such fu- 
sion of adjacent laterals is not character- 
istic of trilacunar nodes in Dubautia, 
3. Trilacunar, verticillate leaves. Examples: 
D. ternifolia^ D. waialealae. The 3 traces of 
each leaf at a node continue downward 
into the vascular cylinder without fusion 
of adjacent laterals. 
4. Multilacunar, opposite (or decussate) 
leaves. Examples: D. laxa (Fig. 14), D. 
laevigata (Fig. 13), U. magnifolia, D. Knud- 
senii. As comparison of Figures 13 and 14 
shows, multilacunar nodes can differ in 
number of traces and in the fusion of 
traces below a node. In D. laxa (Fig. 14), 
each leaf is provided with 5 (or 6) traces, 
which continue downward into the vascu- 
lar cylinder independently. The most lat- 
eral traces in each leaf base increase the 
number of veins in the leaf margin by 
branching toward the margin. In D. laevi- 
gata (Fig. 13), more numerous traces con- 
Figs. 7-10. Portions of cleared leaves to show venation. (7) D. latifolia; margin at left; X 10.5. (8) D. micro- 
cephala, X 13.5. (9) D. linearis; margin at right; X 9.5. (10) Wilkesia g^mnoxiphium; margin below; X 9.5. 
