1921] ARBER—AMARYLLIIDS I05 
true lamina. That the anatomical type shown in figs. 4 and 5 is 
indeed a reduction from that shown in fig. 3, and that the series 
should not be read in the reverse direction, are suggested by the 
general morphology of the subgenus Corbularia. The extreme 
corona development and the tendency to zygomorphy in the hoop- 
petticoat daffodil, as CHurcu™ has suggested, point to its being 
a more advanced and specialized type than the various forms of 
Eunarcissus. 
Pseudo-lamina of Eurycles 
The leaf of Eurycles sylvestris Salisb. furnishes a very char- 
acteristic example of what has elsewhere? been described as the 
““pseudo-lamina’’ of the monocotyledon. The blade (fig. 7) is 
large. A herbarium specimen was measured in which it was 19 cm. 
long by 25.5 cm. wide. Fig. 7 shows that the primary skeletal 
system of this pseudo-lamina may well be interpreted as originating 
by the separation of the veins of the distal end of the petiole. The 
secondary and tertiary venation is also of interest from this point 
of view (fig. 8). A very large number of the secondary veins are 
unbranched and unconnected, and it is noticeable that the tertiary 
veins are extremely irregular; some pass from one secondary vein 
to another, some go from one secondary vein to a primary; while 
others leave a secondary vein, form a loop, and return to the vein 
whence they arose. The anomalous character of this venation 
seems not inconsistent with the view that the blade of the mono- 
cotyledon is an organ which is still at the experimental stage of its 
evolution from an expanded petiole. 
Batrour LaporaTory 
CAMBRIDGE, ENGLAND 
3 Cuurcu, A. H., Types of floral mechanism. Part I. Oxford. 1908. 
