482 Agnes Arber .— The Phyllode Theory of 
SCHEUCHZERIACEAE. 
* Trigl'ochin maritimum , L. In the solid, non-sheathing upper part of 
the leaf, the present writer has found, in agreement with Areschoug’s 1 
observation, a median, normally orientated bundle, two main laterals 
obliquely placed, and a series of peripheral bundles with the xylem directed 
inwards; the peripheral bundles towards the adaxial face are thus inversely 
orientated as compared with those of a normal lamina (Fig. 10, p. 479). 
T. G. Hill, who has also described the anatomy of the leaf, figures the 
vascular strands towards the adaxial surface as though their xylem were 
directed upwards. 2 This is apparently an error ; the bundles are small and 
their inversion may easily be overlooked. 
Scheuchzeria palustris , L. According to Raunkiser, 3 the anatomy of 
the leaf of this plant is essentially similar to that of Triglochin maritimum . 
Butomaceae. 
Butomus umbellatus , L. Sauvageau 4 describes the leaves as phyllodic ; 
he says that the triangular transverse section shows an arc of normal 
bundles and a peripheral series of numerous small bundles. Sauvageau does 
not explicitly describe the orientation of these outer bundles, which seem to 
be somewhat reduced. 
JUNCACEAE, LlLIACEAE, AND AMARYLLIDACEAE. 5 
It is unnecessary to enter into details here concerning these Families, 
since it has long been known that they contain, besides numerous cases of 
leaves with a single row of normally orientated bundles, other cases of leaves 
thickened in various degrees, or even almost radially symmetrical, in which 
inverted bundles with the xylem directed downwards occur towards the 
adaxial face (Figs. 6-9, 12-14, p. 479). Such a leaf as that of Allium Cepa , 
L. (Fig. 9, p. 479), may be closely compared with a cylindrical Dicotyle¬ 
donous phyllode, such as that of Acacia scirpifolia , Meissn. (Fig. 1 B, p. 474). 
A third class of cases is even more striking from the point of view of the 
phyllode theory—that, namely, in which the leaf is not markedly thick, but 
in which there is, nevertheless, a series of inverted bundles towards the 
adaxial face, in addition to the normal series, e. g. Eremurus himalaicus , 
Baker (Fig. 6, p. 479), and Narcissus pseudo-narcissus , L. (Fig. 14, p. 479). 
The isobilateral equitant leaves belonging to these and other Families we 
shall consider in the next section of this paper. 
4. The isobilateral equitant leaf and its relation to other 
phyllodic types. 
The type of leaf occurring in many species of Iris and described as 
‘ equitant 5 is, as is well known, characterized by a sheathing leaf-base, 
1 Areschoug, F. W. C. (1878). 2 Hill, T. G. (1900), PI. VI, Fig. 7. 
3 Raunkiser, C. (1S96). 4 Sauvageau, C. (1893). 
6 The present writer proposes to deal further with these Families in a later paper. 
