236 Salisbury*— The Extra-floral Nectaries of the 
These cells appear to be of two kinds, some show a deeply stained 
protoplasm, the rest stain but faintly and contain large nuclei. The staining 
reagents used being Methyl blue and 
\ , Kleinenberg’s hematoxylin and safranin. 
Polygonum multiflorum . 
The nectary here is triangular in form ; 
only slightly depressed, and with poorly 
differentiated lips. Immediately beneath the 
nectary are from 2-3 layers of sclerized and 
pitted cells, between these and the bundle 
are parenchymatous cells interspersed with 
sclerenchymatous groups. The median 
petiolar bundle has a sclerotic sheath which is 
perforated opposite the nectary (PI. XVI, 
Fig. 8). Calcium oxalate sphaerocrystals 
occur around the gland and mucilage cells 
are present in the leaf-epidermis. The petiole is of a rounded pentagonal 
form ; the bundles of the upper angles are somewhat reduced. 
Fig. 6. Pitted epithem of Polygonum 
sachalinense. 
Polygonum scandens. 
The nectary is slit-like, measuring about o*8 x 075 mm. Immediately 
beneath are two layers of sclerized and pitted cells, and between these and 
the bundle 3-4 layers of cells (PI. XVI, Fig. 3). 
The chief interest of this species lies in the fact that it possesses at once 
the smallest nectary and most reduced petiolar structure of all the species 
examined. The petiole, which has a deep groove on the upper surface, has 
six bundles ; but two of these, situated in the wings bordering the groove, 
are extremely reduced (PI. XVI, Fig. 12). What appear to be wax glands 
occur on the leaf-blade. 
Polygonum baldschuanicum . 
The nectary here is not well developed, and the lip is poorly differ- 
entiated ; the underlying tissue is sclerized and pitted, and between this and 
the bundle is parenchymatous tissue. The petiole is rounded — pentagonal 
in outline ; it contains six bundles, the upper two being small. An interest- 
ing feature of this species, which is a woody climber, is that nectaries are 
absent from the rosette of leaves at the base of the annual shoots ; in some 
cases it was not till the eighth leaf that the nectary was present. 
Polygonum Co7tvolvulus. 
This species has a somewhat small elongated nectary of triangular 
form about 0*9 mm. long by 0*5 mm. as its greatest breadth. The lips are 
