404 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
type, as found in Ulmus, Morus, Madura, and Urtica, representatives of 
the three famihes of the order, is an ovule supply which is the result of the 
fusion of two lateral strands from the floral axis. The second type is found 
in Celtis and in Laportea, where the ovule supply is a branch from the 
anterior carpellary strand. The third type is in Humulus and in Cannabis, 
where the ovule supply is a continuation of a single strand from the pedicel. 
The first two suggest a foliar origin for the ovules. The two lateral 
strands passing to the ovule are two lateral basal veins arising with the 
mid vein of the ar.terior carpel. This condition strongly suggests the carpel 
to be a foliar organ with palmate venation. Possibly the ancestral condi- 
tion was that of a carpel with several ovules, two at least, one borne on each 
of these basal lateral veins ; but through coalescence and reduction the two 
veins conjoined and one ovule was crowded out. It is likely that other 
lateral veins of the dorsal carpellary bundle above the two existing bearing 
ovules have disappeared through the same processes. The same thing 
seems to have happened in the posterior carpel of Ulmus. An abortive 
ovulary branch of the placental strand, in which are incorporated the 
abortive lateral strands (basal veins) in the anterior and posterior carpels, 
is present just opposite the branch passing into the ovule (PI. XVI, fig. 19, 
i^; PI. I, fig. 3, i^). The ovule belonging with this strand is occasionally 
present in Ulmus and in Morus (Baillon, i ; Engler, 9). The strand leading 
to the ovule in Humulus and in Cannabis arises deep in the pedicel. It is 
posterior and opposite to the strand that passes into the enveloping bract 
(PI. XX, fig. 2, 0, a), and is the largest of the four strands in the pedicel. 
The single pedicellar strand to the ovule and the phenomenon present 
there are due undoubtedly to the greatly reduced state of the flowers, 
described previously (p. 402), which has altered the ovule supply to a single 
strand. In the anterior carpel the lateral carpellary veins have disappeared 
and the midrib is small, undoubtedly because of the development of the large 
bract. The same bundles in the posterior carpel have fused into one strand 
passing to the single ovule. The ovule and the ovule supply, therefore, 
indicate a natural order for the Ulmaceae, Moraceae, and Urticaceae. 
When the ovule of the Urticales is taken into consideration to determine the 
likely relationship of the order, the type of ovule as found in Ulmaceae 
must be used. That type is the anatropous, pendulous, or lateral ovule, 
which is the primitive type in the Urticales. The partial basal or basal- 
erect ovules are the result of reduction as the comparative anatomical 
studies previously described indicate. 
The accepted relationship of these three families on the part of taxono- 
mists is supported by this study of floral anatomy. The Urticaceae are higher 
than the Moraceae, i.e., they are more reduced in carpels and in perianth. 
The Moraceae are higher than the Ulmaceae, i.e., they are more reduced 
in number of stamens and in perianth parts. Also, the generic relationships 
are indicated by this anatomical study. In the Urticaceae, Laportea and 
