214 Parkin*—Observations on Latex and its Functions. 
EXPLANATION OF FIGURES IN PLATE XII. 
Illustrating Mr. Parkin’s paper on Latex and its Functions. 
The figures all refer to Hevea brasiliensis . 
Fig. i. Diagram of the attachment of the petiole to the stem (nat. size). p., 
petiole; s., stem; b., axillary bud; sc., scar of stipule. The rest is explained in 
the text. 
Figs. 2-6 refer to the laticiferous system of the young seed. 
Figs. 2 and 3. Diagrams of median longitudinal and transverse sections respec¬ 
tively of young seed, which is nearly full size, but considerably off maturity ( x 3). 
/at., laticiferous tissue exaggerated in size; /., funicle; r., raphe with main 
fibrovascular bundle; c., chalaza; oi., outer integument; ii., inner integument 
with fibrovascular bundles; ol., outer limiting layer of cells of inner integument 
which lengthen greatly in the radial direction and sclerose to form the hard coat 
of the seed; il., inner limiting layer of cells of the inner integument, external to 
which is situated the laticiferous tissue; n., remains of nucellus; e., developing 
endosperm; em., embryo; m ., micropyle ; cc., central cavity. 
Fig. 4. Early stage in the formation of the laticiferous tissue (x 550). lat., 
three laticiferous cells differentiated from the surrounding parenchymatous cells; 
il., inner limiting layer of cells of inner integument; n., outer layer of cells of 
nucellus. 
Fig. 5. A piece of the laticiferous tissue at a later stage (x 550); cells in 
communication, due to the partial dissolution of the intervening walls, p., pro¬ 
cess ; n., nucleus. 
Fig. 6. Portion of laticiferous tissue fully developed; cell-walls only represented, 
contents having been dissolved out by chloroform. Note the partial dissolution 
of the intervening walls of the laticiferous cells and the long processes given 
out. (x 55°0 
