461 
considered in Relation to the Phyllode Theory . 
Of Allium Dioscoridis, Sibth. et Sm. (Section Nectaroscordum ), I have 
only been able to examine one small piece of the limb of a leaf from Sicily. 
The structure is sufficiently striking — the limb is thin and is furnished with 
a single series of bundles, but from the midrib region a plate-like keel 
originates {k, Fig. 30 a). The herbarium material at my disposal did not 
enable me to satisfy myself about the orientation of the bundles, except those 
on the margins of the limb, which are placed horizontally (Fig. 30 B ; see 
also pp. 463-4). This account must be considered as purely provisional ; 
I hope to get further material and to study the peculiar structure of this leaf 
in detail. Its ground-plan appears to recall that of certain Iridaceous 
leaves, but it remains to be seen whether this comparison can be main- 
tained. 
In the case of Allium Monanthum , Maxim. (Sect. Microscordum ), I have 
again not been able, owing to paucity of material, to examine the structure 
adequately. The fragment of a leaf from Japan, which I sectioned, showed, 
however, a general similarity to that of A. Moly. At the base there was 
an apparent petiole (Fig. 31 a), probably of sheath nature, while the limb 
had one series of normally orientated bundles (Fig. 31c). 
Brodiaea congesta , Sm., another member of the Allieae, has scale 
leaves with a single row of normally orientated bundles (Fig. 32 D), and also 
phyllodic foliage leaves with inverted as well as normal bundles (Figs. 
32A-D). I regard the latter as petiolar, and the former as of leaf-base 
nature. At the extreme apex, the foliage leaf becomes almost cylindrical 
(Fig. 32 c). The most striking feature of the anatomy is the presence of 
a median inverted bundle which is larger than the midrib (m.i.b. in Figs. 
32 a-d). This peculiarity can be paralleled in the petioles of certain 
Polygonaceae, e. g. Polygonum amphibium , L. (Fig. 33), and Antigonon 
leptopiis , Hook, et Arn. (Fig. 35). This median inverted strand must not be 
claimed, however, as an exclusively petiolar character, since in Polygonum 
amphibium it persists into the midrib. 
V. The Leaves of Astelia and Dasylirion (Dracaenoideae). 
Predominance of the main laterals, associated with relative insigni- 
ficance of the median bundle — a somewhat different thing from the lack of 
well-defined symmetry about a midrib referred to on p. 449 — is a notice- 
able character of the leaf of certain members of the genus Astelia (Dracae- 
noideae). I have seen it in sections of A. Solandri , A. Cunn. (Fig. 34), and 
A. Banksii ) A. Cunn., and, judging from the external appearance, the same 
thing occurs in A.grandis , Hook, f., and A. trinervia , T. Kirk. In A. alpina , 
R. Br., on the other hand, the three main strands are almost equal in size. 
A similar small midrib with large main laterals occurs in Allium Schoeno - 
peculiarities of leaf structure to which she draws attention are precisely those on which this theory 
throws light. 
