477 
the Monocotyledonous Leaf\ 
can logically be used as evidence of phyllodic origin. For instance, Melo- 
canna bambusoides , Trin., of the Gramineae, is not included, although 
it has inverted bundles in the midrib. 1 
(v) Trfoul's Theory. 
So far as has been ascertained, the only botanist who ever drew mor¬ 
phological conclusions from the existence of the type of leaf anatomy, 
here called ‘phyllpdic’, was Trecul. 2 In 1876 he published a paper dealing 
with the Amaryllidaceae, and incidentally with the Liliaceae, in which he 
compared the anatomy of the leaves of various species of Agave, Narcissus , 
Allium , and Aloe to that of inflorescence axes. He drew the conclusion 
that these leaves were really stem structures. It is obviously impossible to 
accept this view for many reasons. Even on anatomical grounds the 
resemblance of these leaves to petioles is far more precise than their 
resemblance to stems, since they are generally symmetrical only about 
a single median plane; this is shown, for instance, in the diagram of an 
Allium leaf, Fig. 9, p. 479. But Trecul’s theory, though untenable, is of 
significance, since it shows that, forty years ago, one botanist had realized 
that the peculiar leaf anatomy of these Monocotyledons demanded a morpho¬ 
logical explanation. The over-insistence on teleological interpretations, 
which was so rife especially in the latter part of the last century, has 
tended, in many cases, to obscure the morphological standpoint. 
2. The occurrence of phyllodic leaf anatomy among 
Monocotyledons. 
(i) Explanation of list of cases (pp. 478-81). 
We now have to make a general inquiry into the occurrence and distri¬ 
bution of inverted foliar bundles among the various Families of Monocotyle¬ 
dons. In the following table (pp. 478-81) the genera in which phyllodic 
leaf structure is known to occur are enumerated. In the course of the 
present study, sections have been cut of selected representatives of most of 
the Families of Monocotyledons accessible to the writer ; those cases of 
phyllode anatomy whose existence is reported here apparently for the first 
time are initialed (A.A.), while those in which the present writer has merely 
confirmed the published accounts are marked with an asterisk. Those in 
which the leaf is differentiated into petiole and ‘ lamina 5 and in which the 
‘ lamina ’ shows phyllodic structure are marked (l) ; those marked (e) have 
isobilateral, equitant leaves with two series of bundles of opposed orientation; 
the remaining genera have leaves either flattened in the normal horizontal 
plane, or more or less thickened, or radially symmetrical, but not expanded 
in the vertical plane. It may be well to note in passing that the present 
writer regards both isobilateral, equitant leaves and these non-vertical leaves 
1 Brandis, D. (1907). 2 Trecul, A. (1876). 
I i % 
