114 BOTANICAL GAZETTE 
It is offered in explanation of this interesting condition of af 
that the supply of light of Tillandsia is considerably diminishec 
_ the presence of the overlapping scales, which are necessary for w 
absorption and for protection against too rapid transpiration. 
order to meet this diminution, it not only prefers sunny e3 
but has modified its chlorophyll-bearing apparatus by caus 
occupy a much larger area in order to utilize to better advantage s 
light as penetrates to the interior of the leaf. 
It may be stated here that precautions were taken to exalt 
healthy festoons removed directly from moss-laden trees. In s 
instances these were examined immediately after such removal, 
confinement in the laboratory should in some way induce pa 
cal conditions. 
THE SCALES. eS 
The scales cover the entire living exposed portion of the plant 
the exception of the corolla, stamens, ovary, and a portion of 
calyx. Each scale develops from a single epidermal cell, the 
divisions of which occur while the young leaves and stems are 
within the leaf sheath. The first division is transverse (Ag. 
The proximal cell thus produced remains undivided, the 
dividing transversely till four cells are produced, of which the 
three form the stalk of the scale (fig. 57). The outermost | 
spherical cell becomes divided into four cells by two longitudinal 
perpendicular to one another (figs. 58 and 63). By periclinal' 
a central group of four cells becomes separated from four oute 
(fig. 64). The central cells divide no further. The outer ones 
by periclinal walls to form two concentric rows (fig. 65): : 
of both rows become eight in number by anticlinal walls, the 
row undergoing no further division, but the outer, by another 
anticlinals, finally has sixteen. A fourth concentric row * 
formed by periclinal walls from the outermost sixteen celles 
three inner layers consist of four, eight, and sixteen cells respet 
which numbers remain constant, but the fourth layer 
repeated divisions till a large number of cells are produce¢ 
These last lengthen greatly and form the wing of the 
surface view of the mature scale is seen in fig. 68, the lo 
section in fig. 70. All of the cells but the stalk cells and the 
